RFR: 8289740: Add verification testing during all concurrent phases in G1 [v2]

[Thomas Schatzl]

> Hi all,
> 
>   can I have reviews for this change that adds a test that causes GCs that do lots of verification in all phases of the concurrent cycle to make sure that verification is working after changes.
> 
> Testing: test case, gha
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9377/files
  - new: https://git.openjdk.org/jdk/pull/9377/files/eed786bd..eed786bd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9377&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9377&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/9377.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9377/head:pull/9377

PR: https://git.openjdk.org/jdk/pull/9377