RFR: 8267293: vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java fails when JTREG_JOBS > 25

[Jie Fu]

Hi all,

vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java fails on our many-core machines due to `-XX:MaxRAMPercentage=0`.
This is because `-XX:MaxRAMPercentage=0` will be 0 if JTREG_JOBS > 25 [1].

We can also reproduce the bug by: `make test TEST="vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java" JTREG="JOBS=26"` on almost all machines.

This fix will make it to be more robust, which is suggested by  @shipilev [2] and many thanks to him.

Thanks.
Best regards,
Jie

[1] https://github.com/openjdk/jdk/blob/master/make/RunTests.gmk#L741
[2] https://github.com/openjdk/jdk/pull/4062#pullrequestreview-661198240

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Commit messages:
 - 8267293: vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java fails when JTREG_JOBS > 25

Changes: https://git.openjdk.java.net/jdk/pull/4076/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=4076&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8267293
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4076.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4076/head:pull/4076

PR: https://git.openjdk.java.net/jdk/pull/4076