[jdk21u-dev] RFR: 8313355: javax/management/remote/mandatory/notif/ListenerScaleTest.java failed with "Exception: Failed: ratio=792.2791601423487"

[Satyen Subramaniam]

Backporting JDK-8313355: javax/management/remote/mandatory/notif/ListenerScaleTest.java failed with "Exception: Failed: ratio=792.2791601423487". The `javax/management/remote/mandatory/notif/ListenerScaleTest.java` test fails intermittently - this change preserves the function of the test, while minimizing/removing intermittent failures. Specifically, the test exists to check that notification work does not scale linearly with number of MBeans, so it calculates a ratio of the time taken with one, and with 20,000 MBeans. We can increase the point at which that calculated ratio is considered a failure: original commit chooses 2500. Ran GHA Sanity Checks, local Tier 1 and 2, and adjusted test. Patch is clean.

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Commit messages:
 - Backport debf0ecfb0076f5513595c74038215520d630764

Changes: https://git.openjdk.org/jdk21u-dev/pull/1849/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1849&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8313355
  Stats: 4 lines in 1 file changed: 2 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1849.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1849/head:pull/1849

PR: https://git.openjdk.org/jdk21u-dev/pull/1849