[jdk21u] RFR: 8312625: Test serviceability/dcmd/vm/TrimLibcHeapTest.java failed: RSS use increased

[Aleksey Shipilev]

Clean backport to stabilize the test.

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Commit messages:
 - Backport 117f42dbe9a78bcf43bdf3873d5d86a19a9092d3

Changes: https://git.openjdk.org/jdk21u/pull/53/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u&pr=53&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312625
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u/pull/53.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/53/head:pull/53

PR: https://git.openjdk.org/jdk21u/pull/53