RFR: 8317575: AArch64: C2_MacroAssembler::fast_lock uses rscratch1 for cmpxchg result [v2]

[Stefan Karlsson]

> Please review this removal a potentially problematic usage of rscratch1 in C2_MacroAssembler::fast_lock.

Stefan Karlsson 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 remote-tracking branch 'upstream/master' into 8317575_aarch64_fast_lock_rscratch1
 - 8317575: AArch64: C2_MacroAssembler::fast_lock uses rscratch1 for cmpxchg result

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/16049/files
  - new: https://git.openjdk.org/jdk/pull/16049/files/a15846b9..ff41a651

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16049&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16049&range=00-01

  Stats: 13449 lines in 474 files changed: 7776 ins; 3388 del; 2285 mod
  Patch: https://git.openjdk.org/jdk/pull/16049.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16049/head:pull/16049

PR: https://git.openjdk.org/jdk/pull/16049