RFR: 8345405: Add JMH showing the regression in 8341649 [v2]

[Eric Caspole]

> This JMH using MethodHandles shows the regression in 8341649, for example comparing 24-b25, which included the regression to today's head. It was an interaction between the runtime and C2 rather than a change in MethodHandles.
> 
> Here are example results from an Ampere platform:
> jdk-24-b25 before the fix:
> Benchmark                (classes)  (instances)   Mode  Cnt   Score   Error   Units
> MethodHandleStress.work       1000          100  thrpt   20  33.423 ± 7.678  ops/ms
> 
> Today's head with the fix:
> Benchmark                (classes)  (instances)   Mode  Cnt    Score    Error   Units
> MethodHandleStress.work       1000          100  thrpt   20  709.249 ± 50.575  ops/ms

Eric Caspole 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:

 - Code cleanups suggested by Claes
 - Merge branch 'master' of https://github.com/openjdk/jdk into JDK-8345405
 - 8345405: Add JMH showing the regression in 8341649

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/22556/files
  - new: https://git.openjdk.org/jdk/pull/22556/files/4c7ee932..977d1e8e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22556&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22556&range=00-01

  Stats: 6671 lines in 258 files changed: 3254 ins; 2397 del; 1020 mod
  Patch: https://git.openjdk.org/jdk/pull/22556.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22556/head:pull/22556

PR: https://git.openjdk.org/jdk/pull/22556