[SPARK-16657] [SQL] Replace children by innerChildren in InsertIntoHadoopFsRelationCommand and CreateHiveTableAsSelectCommand

[gatorsmile]

What changes were proposed in this pull request?

The query in InsertIntoHadoopFsRelationCommand and CreateHiveTableAsSelectCommand should be treated as inner children, like what we did for the other similar nodes: CreateDataSourceTableAsSelectCommand, innerChildren, and InsertIntoDataSourceCommand.

The explain will be improved.
Before:

ExecutedCommand
:  +- CreateHiveTableAsSelectCommand [Database:default}, TableName: tab1, InsertIntoHiveTable]
:     +- Project [1 AS 1#13, 3 AS 3#14]
:        +- OneRowRelation$

After:

ExecutedCommand
:  +- CreateHiveTableAsSelectCommand [Database:default}, TableName: tab1, InsertIntoHiveTable]
:     :  +- Project [1 AS 1#13, 3 AS 3#14]
:     :     +- OneRowRelation$

How was this patch tested?

N/A

[SparkQA]

Test build #62638 has finished for PR 14290 at commit e0605cd.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[gatorsmile]

The analyzer resolution requires them as children. Although this is inconsistent with the other similar nodes, we still can tolerate it.