RFR: 8371852: Shenandoah: Remove unused ShenandoahFreeSet::_allocated_sinc… [v2]

[Nityanand Rai]

> Removed the unused _allocated_since_gc_start[UIntNumPartitions] field from ShenandoahRegionPartitions class. This field became obsolete after JDK-8365880 unified memory usage accounting in ShenandoahFreeSet but was not cleaned up.

Nityanand Rai 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 two additional commits since the last revision:

 - Merge branch 'openjdk:master' into 8371852-nityanar
 - 8371852: Shenandoah: Remove unused ShenandoahFreeSet::_allocated_since_gc_start field
   
   Removed the unused _allocated_since_gc_start[UIntNumPartitions] field from
   ShenandoahRegionPartitions class. This field became obsolete after JDK-8365880
   unified memory usage accounting in ShenandoahFreeSet but was not cleaned up.
   
   Reviewed-by: TBD

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/28332/files
  - new: https://git.openjdk.org/jdk/pull/28332/files/e7dbd54e..887d25e2

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28332&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28332&range=00-01

  Stats: 164817 lines in 903 files changed: 113165 ins; 23348 del; 28304 mod
  Patch: https://git.openjdk.org/jdk/pull/28332.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28332/head:pull/28332

PR: https://git.openjdk.org/jdk/pull/28332