RFR: 8322978: Remove debug agent debugMonitorTimedWait() function. It is no longer used.

[Chris Plummer]

Remove unused debugMonitorTimedWait() function.

Tested with all of tier1, and also ran tier2 and tier4 svc tests.

I'd like to push this as a trivial change.

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Commit messages:
 - Remove unused debugMonitorTimedWait() function.

Changes: https://git.openjdk.org/jdk/pull/17260/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17260&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8322978
  Stats: 20 lines in 2 files changed: 0 ins; 18 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/17260.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17260/head:pull/17260

PR: https://git.openjdk.org/jdk/pull/17260