[SPARK-28388][SQL][TEST] Port select_implicit.sql

[wangyum]

What changes were proposed in this pull request?

This PR is to port numeric.sql from PostgreSQL regression tests. https://github.com/postgres/postgres/blob/REL_12_BETA2/src/test/regress/sql/select_implicit.sql

The expected results can be found in the link: https://github.com/postgres/postgres/blob/REL_12_BETA2/src/test/regress/expected/select_implicit.out

When porting the test cases, found one PostgreSQL specific features that do not exist in Spark SQL:
SPARK-28329: SELECT INTO syntax

How was this patch tested?

N/A

[SparkQA]

Test build #107648 has finished for PR 25152 at commit a183e2d.

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

[SparkQA]

Test build #107743 has finished for PR 25152 at commit c00b9d8.

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

[dongjoon-hyun]

Retest this please.

[SparkQA]

Test build #107804 has finished for PR 25152 at commit c00b9d8.

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

[dongjoon-hyun]

+1, LGTM. Merged to master.
Thank you, @wangyum !