RFR: 8368668: Several vmTestbase/vm/gc/compact tests timed out on large memory machine [v2]

[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.

SendaoYan has updated the pull request incrementally with one additional commit since the last revision:

  Add -Xmx2G for vmTestbase/gc/gctests/AllocateWithoutOomTest/AllocateWithoutOomTest.java

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/27488/files
  - new: https://git.openjdk.org/jdk/pull/27488/files/c337af53..7e10e171

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27488&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27488&range=00-01

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 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