RFR: 8318479: [jmh] the test security.CacheBench failed for multiple threads run

[Daniel Jeliński]

Remove the hardcoded maximum heap size.

Verified that the benchmark now passes with 100 threads given sufficient heap:

make test TEST=micro:CacheBench MICRO="OPTIONS=-t 100;JAVA_OPTIONS=-Xmx16g"

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Commit messages:
 - Remove hardcoded Xmx

Changes: https://git.openjdk.org/jdk/pull/16315/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16315&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318479
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/16315.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16315/head:pull/16315

PR: https://git.openjdk.org/jdk/pull/16315