RFR: 8304804: Remove develop flag G1VerifyCTCleanup [v2]

[Thomas Schatzl]

> Hi all,
> 
>   please review the removal of the develop `G1VerifyCTCleanup` option. This develop flag seems to be not worth keeping as regular verification (`VerifyAfterGC`) performs this one anyway, and if it's too heavyweight it is trivial to add again for debugging.
> 
> There also seems to be no particular reason compared to others why you would specifically need card table verification more than other.
> 
> Testing: local compilation, gha
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:

 - Merge branch 'master' into pull/13166
 - 8304804
   
   initial version

-------------

Changes: https://git.openjdk.org/jdk/pull/13166/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13166&range=01
  Stats: 4 lines in 2 files changed: 0 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/13166.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13166/head:pull/13166

PR: https://git.openjdk.org/jdk/pull/13166