RFR: 8357481: Excessive CompileTask wait/notify monitor creation [v2]

[Aleksey Shipilev]

> See bug for rationale.
> 
> This PR implements the 2nd solution from the bug: lift the lock to be global. As described in the bug, excess locking work would realistically affect Xcomp, and only in a minor way. But we will reap a minor footprint/latency benefit by not constructing the lock for every `CompileTask`.
> 
> Additional testing:
>  - [x] Linux x86_64 server fastdebug, `compiler`
>  - [x] Linux x86_64 server fastdebug, `all`
>  - [x] Linux AArch64 server fastdebug, `all`

Aleksey Shipilev 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 'master' into JDK-8357481-compile-task-lock
 - Fix

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25364/files
  - new: https://git.openjdk.org/jdk/pull/25364/files/65ad15e0..5b781e16

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25364&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25364&range=00-01

  Stats: 36369 lines in 510 files changed: 26768 ins; 7242 del; 2359 mod
  Patch: https://git.openjdk.org/jdk/pull/25364.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25364/head:pull/25364

PR: https://git.openjdk.org/jdk/pull/25364