Remove duplicate category_name, cat and tag_id from ES query when tax_query set

[rebeccahum]

Description

Core has a funky backwards compat feature where category_name, cat and tag_id are set explicitly:

https://github.com/WordPress/WordPress/blob/5d99107bf3ab35aa3dda82c6b3903f5717771335/wp-includes/class-wp-query.php#L2193-L2215

However, this interferes with the ES query when tax_query is also set. For example, take this WP_Query to be offloaded:

	$args = array(
		'es' => true,
		'post_type' => 'post',
		'tax_query' => array(
			'relation' => 'OR',
			array(
				'taxonomy' => 'post_tag',
				'field'    => 'slug',
				'terms'    => array( 'toronto-traffic' ),
			),
			array(
				'relation' => 'AND',
					array(
						'taxonomy' => 'post_tag',
						'field'    => 'slug',
						'terms'    => array( 'toronto' ),
					),
					array(
						'taxonomy' => 'category',
						'field'    => 'slug',
						'terms'    => array( 'traffic' ),
					),
			),
		),

What we would expect from this is posts with a tag of toronto-traffic OR category of traffic and post_tag of toronto. The ES query would look like:

{
    "from": 0,
    "size": 10,
    "sort": [
        {
            "post_date": {
                "order": "desc"
            }
        }
    ],
    "query": {
        "match_all": {
            "boost": 1
        }
    },
    "post_filter": {
        "bool": {
            "must": [
                {
                    "bool": {
                        "should": [
                            {
                                "terms": {
                                    "terms.post_tag.slug": [
                                        "toronto-traffic"
                                    ]
                                }
                            },
                            {
                                "bool": {
                                    "must": [
                                        {
                                            "terms": {
                                                "terms.post_tag.slug": [
                                                    "toronto"
                                                ]
                                            }
                                        },
                                        {
                                            "terms": {
                                                "terms.category.slug": [
                                                    "traffic"
                                                ]
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                },
                {
                    "terms": {
                        "post_type.raw": [
                            "post"
                        ]
                    }
                },
                {
                    "terms": {
                        "post_status": [
                            "publish"
                        ]
                    }
                }
            ]
        }
    },
    "track_total_hits": true
}

However, ES currently returns the following query, where results that may only just have traffic as a category are returned:

{
    "from": 0,
    "size": 10,
    "sort": [
        {
            "post_date": {
                "order": "desc"
            }
        }
    ],
    "query": {
        "match_all": {
            "boost": 1
        }
    },
    "post_filter": {
        "bool": {
            "must": [
                {
                    "bool": {
                        "should": [
                            {
                                "terms": {
                                    "terms.post_tag.slug": [
                                        "toronto-traffic"
                                    ]
                                }
                            },
                            {
                                "bool": {
                                    "must": [
                                        {
                                            "terms": {
                                                "terms.post_tag.slug": [
                                                    "toronto"
                                                ]
                                            }
                                        },
                                        {
                                            "terms": {
                                                "terms.category.slug": [
                                                    "traffic"
                                                ]
                                            }
                                        }
                                    ]
                                }
                            },
                            {
                                "terms": {
                                    "terms.category.slug": [
                                        "traffic"
                                    ]
                                }
                            },
                            {
                                "terms": {
                                    "terms.category.term_id": [
                                        12345 // traffic category term_id
                                    ]
                                }
                            },
                            {
                                "terms": {
                                    "terms.post_tag.term_id": [
                                        6789 // toronto-traffic post_tag 
                                    ]
                                }
                            }
                        ]
                    }
                },
                {
                    "terms": {
                        "post_type.raw": [
                            "post"
                        ]
                    }
                },
                {
                    "terms": {
                        "post_status": [
                            "publish"
                        ]
                    }
                }
            ]
        }
    },
    "track_total_hits": true
}

It ends up treating the three conditions separately as an OR.

Checklist

Please make sure the items below have been covered before requesting a review:

• This change works and has been tested locally (or has an appropriate fallback).
• This change works and has been tested on a Go sandbox.
• This change has relevant unit tests (if applicable).
• This change has relevant documentation additions / updates (if applicable).

Steps to Test

1. Create post A and only assign it to category traffic.
2. Create post B and assign it to category traffic and post_tag toronto.
3. Create post C and assign it to post_tag toronto-traffic.
4. Offload the WP_Query described in description.
5. You will see that post A will be returned in the results (when it shouldn't be).
6. Apply patch.
7. You will not see post A returned in the results anymore.

[rinatkhaziev]

Discussed in Slack, should be fine 🚢
But we should test thoroughly before merging to prod.

[rogertheriault]

Hiding whitespace changes is helpful, only 3 lines actually "changed"