ddl: Do not succee the last_gc_safepoint when physically dropping table is skipped (#8910)

[ti-chi-bot]

This is an automated cherry-pick of #8910

What problem does this PR solve?

Issue Number: close #8911

Problem Summary:
In #8721, we introduce a rule that: "if the regions of a given table is not totally removed from TiFlash, skip physically dropping it". However, it does not set the succeeded = false, so after all it will update the last_gc_safepoint.
When the whole cluster has few write commands, the gc_safepoint may not change. It make that the physically dropping only run after the gc_safepoint is changed again. Which will slow down the data disk reclaim.

What is changed and how it works?

• If physically dropping a table is skipped by regions are not totally removed, set succeeded = false
• Then the last_gc_safepoint will not get updated
• And after ddl_sync_interval_seconds passed, SchemaSyncService::gc will run again even if the gc_safepoint on PD side is not changed

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

[JaySon-Huang]

/run-all-tests

[CalvinNeo]

lgtm

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CalvinNeo, JaySon-Huang

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-04-09 06:28:49.708711339 +0000 UTC m=+943791.236251885: ☑️ agreed by CalvinNeo.
• 2024-04-09 11:41:22.697676236 +0000 UTC m=+962544.225216775: ☑️ agreed by JaySon-Huang.