This is an automated cherry-pick of #8955

What problem does this PR solve?

Issue Number: close #8911

Problem Summary:

After #8910, if some tables are not able to be dropped, SchemaSyncService::gcImpl will run again with the same gc_safepoint.
But in this path, SchemaSyncService::gcImpl always return true. So if there are some tables can not be dropped for some bugs, then this function will run again and again and print lots of loggings.

What is changed and how it works?

if succeeded == false, then let SchemaSyncService::gcImpl run again after ddl_sync_interval_seconds

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

None