RFR: 8368668: Several vmTestbase/vm/gc/compact tests timed out

[SendaoYan]

Hi all,

Several vmTestbase/vm/gc/compact tests was observed timed out after JDK-8260555 set the default jtreg timeout factor to 1. The test log shows that test detect 448 threads and 30GB(32178700288) memory. Seems that this stress make tests can not finish in 120s.

This PR add '-Xmx2G' to decrease the test stress and make these tests run success steady.

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Commit messages:
 - 8368668: Several vmTestbase/vm/gc/compact tests timed out

Changes: https://git.openjdk.org/jdk/pull/27488/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27488&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8368668
  Stats: 18 lines in 9 files changed: 9 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/27488.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27488/head:pull/27488

PR: https://git.openjdk.org/jdk/pull/27488