RFR: 8348829: Remove ObjectMonitor perf counters [v2]

[Aleksey Shipilev]

> See bug for more discussion. I believe these counters are useless and come with more trouble than their worth.

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains two commits:

 - Merge branch 'master' into JDK-8348829-remove-om-counters
 - Counters removal

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Changes: https://git.openjdk.org/jdk/pull/23326/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23326&range=01
  Stats: 118 lines in 4 files changed: 0 ins; 118 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/23326.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23326/head:pull/23326

PR: https://git.openjdk.org/jdk/pull/23326