[SPARK-28136][SQL][TEST] Port int8.sql

[wangyum]

What changes were proposed in this pull request?

This PR is to port int8.sql from PostgreSQL regression tests. https://github.com/postgres/postgres/blob/REL_12_BETA2/src/test/regress/sql/int8.sql

The expected results can be found in the link: https://github.com/postgres/postgres/blob/REL_12_BETA2/src/test/regress/expected/int8.out

When porting the test cases, found two PostgreSQL specific features that do not exist in Spark SQL:
SPARK-28137: Missing Data Type Formatting Functions
SPARK-28027: Missing some mathematical operators

Also, found three inconsistent behavior:
SPARK-26218: Throw exception on overflow for integers
SPARK-27923: Spark SQL insert bad inputs to NULL
SPARK-28028: Cast numeric to integral type need round
SPARK-2659: HiveQL: Division operator should always perform fractional division, for example:

select 1/2;

How was this patch tested?

N/A

[SparkQA]

Test build #106766 has finished for PR 24933 at commit b5981f5.

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

[SparkQA]

Test build #107392 has finished for PR 24933 at commit a4f649f.

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

[HyukjinKwon]

retest this please

[SparkQA]

Test build #107406 has finished for PR 24933 at commit a4f649f.

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

[dongjoon-hyun]

I updated the PR description by replacing SPARK-28024 with SPARK-26218. For the PR, you need to update only two lines mentioning JIRA. For the others, this looks good.

In the previous int2.sql PR, I didn't see their comments. Sorry about missing that. Let's proceed this one according to their comments and move forward.

[dongjoon-hyun]

+1, LGTM. Merged to master.
The last commit is only updating comments and I also tested this int8.sql locally.

Thank you, @wangyum and @HyukjinKwon .

[SparkQA]

Test build #107421 has finished for PR 24933 at commit 8b22e1f.

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

[SparkQA]

Test build #107425 has finished for PR 24933 at commit bd3a6c3.

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