RFR: 8332448: Make SpaceMangler inherit AllStatic [v2]

[Albert Mingkun Yang]

> Extract the state for `top` out of `SpaceMangler`. Users (Serial and Parallel GC) already tracks the top before/after GC. The "real" change in this PR are only two places: `serialFullGC.cpp` and `PSParallelCompact::post_compact`.
> 
> Test: tier1-5

Albert Mingkun Yang 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. The pull request contains three additional commits since the last revision:

 - review
 - Merge branch 'master' into mangle
 - mangle

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19279/files
  - new: https://git.openjdk.org/jdk/pull/19279/files/27c35a9b..e1d524cc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19279&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19279&range=00-01

  Stats: 33588 lines in 360 files changed: 29030 ins; 3490 del; 1068 mod
  Patch: https://git.openjdk.org/jdk/pull/19279.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19279/head:pull/19279

PR: https://git.openjdk.org/jdk/pull/19279