[SPARK-28950][SQL] Refine the code of DELETE

[xy-xin]

What changes were proposed in this pull request?

This pr refines the code of DELETE, including, 1, make whereClause to be optional, in which case DELETE will delete all of the data of a table; 2, add more test cases; 3, some other refines.
This is a following-up of SPARK-28351.

Why are the changes needed?

An optional where clause in DELETE respects the SQL standard.

Does this PR introduce any user-facing change?

Yes. But since this is a non-released feature, this change does not have any end-user affects.

How was this patch tested?

New case is added.

[SparkQA]

Test build #110018 has finished for PR 25652 at commit c0c9383.

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

[maropu]

retest this please

[SparkQA]

Test build #110100 has finished for PR 25652 at commit c0c9383.

• This patch fails due to an unknown error code, -9.
• This patch merges cleanly.
• This patch adds no public classes.

[maropu]

retest this please

[SparkQA]

Test build #110107 has finished for PR 25652 at commit c0c9383.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[xy-xin]

Updated the code to sync the modification for both DELETE and UPDATE. And once #25626 gets in, will rebase it against the latest code.

[SparkQA]

Test build #110133 has finished for PR 25652 at commit 3080d82.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[cloud-fan]

looks good, @xianyinxin can you rebase?

[xy-xin]

Rebased the code against latest master.
BTW, 1, the keywords description for 'DELETE' 'FROM' is already in sql-keywords.md; 2, document for DELETE need to be add in another pr.

[SparkQA]

Test build #110777 has finished for PR 25652 at commit 65250f3.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[cloud-fan]

thanks, merging to master!

[xy-xin]

Thanks @cloud-fan for reviewing!