RFR: 8343298: Improve stability of runtime/cds/DeterministicDump.java test

[Thomas Schatzl]

Hi all,

  please review this change to make `runtime/cds/DeterministicDump.java` more reliable in presence of GC changes (which https://bugs.openjdk.org/browse/JDK-8295269 stumbled over).

This includes some change to strip the gc age from the dumped objects, but mainly trying to fix heap sizes etc so that GCs are executed consistently (i.e. not at all) in this test.

Testing: tier5, running the test a few thousand times

Thanks,
  Thomas

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Commit messages:
 - * remove deleted newline change
 - * fix heap size for test

Changes: https://git.openjdk.org/jdk/pull/21871/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21871&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343298
  Stats: 13 lines in 2 files changed: 10 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/21871.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21871/head:pull/21871

PR: https://git.openjdk.org/jdk/pull/21871