jmx-dev RFR: 8343936: Adjust timeout in test javax/management/monitor/DerivedGaugeMonitorTest.java

[Kevin Walls]

Test timeout change to cope with -Xcomp runs.
Long-standing problemlisted test.

With -Xcomp locally I could see a failure on the second attempt.
After this change, ran more runs locally and 40 runs per platform in CI are OK.

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Commit messages:
 - Merge remote-tracking branch 'upstream/master' into 8042211_DerivedGaugeMonitorTest
 - 8042211: javax/management/monitor/DerivedGaugeMonitorTest.java AByte: Count down not reached

Changes: https://git.openjdk.org/jdk/pull/22008/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22008&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343936
  Stats: 6 lines in 2 files changed: 2 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/22008.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22008/head:pull/22008

PR: https://git.openjdk.org/jdk/pull/22008