[jdk11u-dev] RFR: 8213695: gc/TestAllocateHeapAtMultiple.java is slow in some configs

[Goetz Lindenmaier]

I backport this for parity with 11.0.17-oracle.

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Commit messages:
 - Backport 755d163e911bae96065298d0abddabf5b0eb3000

Changes: https://git.openjdk.org/jdk11u-dev/pull/1151/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1151&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8213695
  Stats: 4 lines in 1 file changed: 0 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1151.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev pull/1151/head:pull/1151

PR: https://git.openjdk.org/jdk11u-dev/pull/1151