Refactor assertCreateTableAsSelect() and assertExplainAnalyze() code

[pdabre12]

Refactored the assertCreateTableAsSelect() and assertExplainAnalyze() to reduce code duplication.

[pdabre12]

@majetideepak Please review.

[majetideepak]

@pdabre12 Can you give a motivation for this refactor? Do we ever call assertCreateTableAsSelect with allowDropTable set to false?

[pdabre12]

@majetideepak Yes, it will be used in #20936.

[majetideepak]

@majetideepak Yes, it will be used in #20936.

Why do we not want to delete the tables in that PR?

[pdabre12]

There is a small discussion about this in PR #20936.
Basically in order to drop tables, I need to set a system property hive.allow-drop-table=true which would mean modifying the file https://github.com/prestodb/presto/blob/dd5b168ff5bdf306de70be19cc37c9797ca00981/presto-native-execution/src/test/java/com/facebook/presto/nativeworker/NativeQueryRunnerUtils.java .

[majetideepak]

There is a small discussion about this in PR #20936.

I commented there. Let's add the system property to the NativeQueryRunner in a separate PR.
I don't think we should allow not dropping the tables.

[pdabre12]

@majetideepak
Added the changes in #21641.
Closing this PR as it's no longer needed.