[jdk17u-dev] RFR: 8275608: runtime/Metaspace/elastic/TestMetaspaceAllocationMT2 too slow

[Thomas Stuefe]

Clean backport of a change making metaspace elastic tests both more reliable and less time consuming.

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Commit messages:
 - Backport d6d82f52d4a4fac037ee9424503f8b7f11a61c40

Changes: https://git.openjdk.java.net/jdk17u-dev/pull/101/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk17u-dev&pr=101&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8275608
  Stats: 43 lines in 5 files changed: 15 ins; 10 del; 18 mod
  Patch: https://git.openjdk.java.net/jdk17u-dev/pull/101.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17u-dev pull/101/head:pull/101

PR: https://git.openjdk.java.net/jdk17u-dev/pull/101