RFR: 8316746: Top of lock-stack does not match the unlocked object [v2]

[Martin Doerr]

> I think we need to support "Top of lock-stack does not match the unlocked object" and take the slow path. Reason: see JBS issue.
> Currently only PPC64, x86_64 and aarch64 code. I'd like to get feedback before implementing it for other platforms (needed for all platforms).

Martin Doerr has updated the pull request incrementally with one additional commit since the last revision:

  Add x86_64 and aarch64 implementation.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15903/files
  - new: https://git.openjdk.org/jdk/pull/15903/files/afa0e86f..83da590b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15903&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15903&range=00-01

  Stats: 36 lines in 2 files changed: 21 ins; 14 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/15903.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15903/head:pull/15903

PR: https://git.openjdk.org/jdk/pull/15903