Add tests for toast in ENR change

[timchang514]

Description

Adding toasts to ENR for temp tables. This was originally introduced as part of #2259 , we are cherry-picking just this change into REL15 to fix an issue with orphaned temp toast table entries.

Issues Resolved

Adding tests for babelfish-for-postgresql/postgresql_modified_for_babelfish#298

Check List

• Commits are signed per the DCO using --signoff

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[coveralls]

Pull Request Test Coverage Report for Build 7659650718

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• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.001%) to 72.76%

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Totals
Change from base Build 7657622274:	-0.001%
Covered Lines:	40924
Relevant Lines:	56245

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💛 - Coveralls