RFR: 8335902: Parallel: Refactor VM_ParallelGCFailedAllocation and VM_ParallelGCSystemGC [v2]

[Albert Mingkun Yang]

> Similar cleanup as https://github.com/openjdk/jdk/pull/19056 but in Parallel. As a result, the corresponding code in `SerialHeap` and `ParallelScavengeHeap` share much similarity.
> 
> The easiest way to review is to start from these two VM operations, `VM_ParallelCollectForAllocation` and `VM_ParallelGCCollect` and follow the new code directly, where one can see how allocation-failure triggers various GCs with different collection efforts.
> 
> Test: tier1-6; perf-neural for dacapo, specjvm2008, specjbb2015 and cachestresser.

Albert Mingkun Yang has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains one commit:

  pgc-vm-operation

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Changes: https://git.openjdk.org/jdk/pull/20077/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20077&range=01
  Stats: 352 lines in 14 files changed: 96 ins; 169 del; 87 mod
  Patch: https://git.openjdk.org/jdk/pull/20077.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20077/head:pull/20077

PR: https://git.openjdk.org/jdk/pull/20077