Add support for PHP 8.1 features, including fixing a retokenization of reserved keywords bug in PHPCS 3.7.0.

Brings them more into line with the Composer scripts in WPCS.

VIPCS needs to be compatible with WordPress Coding Standards 3.0.0, which is currently in development on its `develop` branch. WPCS now uses some extra dependencies, which are also in development, so we need to allow for a minimum-stability of dev. Run `composer update -W` to pull those extra dependencies in.

Uses the composer-normalize plugin to keep a consistent order.

WordPress-Extra will no longer use the `Generic.Arrays.DisallowShortArraySyntax` rule, but does use the improved `Universal.Arrays.DisallowShortArraySyntax` from PHPCSExtra instead, so whilst we have short array syntax being used in the VIPCS sniffs, let's continue to exclude the rule.

The previous `Sniff::merge_custom_array()` function was moved to a new Helper class in WPCS: WordPress/WordPress-Coding-Standards#2157.

However, it is marked as non-public (only meant for WPCS directly), so copying into the VIPCS sniff is easiest for now.

This is more tested than the WPCS Sniff::addMessage().

VIPCS makes use of PHPCSUtils directly (such as for MessageHelper), so it should be marked as such in the Composer config.

Shows up empty in Ci and locally.

The ruleset tests were failing mainly due to WordPress/WordPress-Coding-Standards#2108 which renamed some violation codes that we were excluding.

The other change to account for was the replacement of a WPCS StrictComparisons sniff with a PHPCSExtras Universal sniff. The sniff in PHPCSExtra contains a fixer. As this is a risky fixer, this fixer is turned off for WPCS. The sniff in PHPCSExtra will provide metrics about loose versus strict comparisons.

Make it clear which ruleset being tested, even on a test failure.

Validate the PHPCS installed standards in the quick test.