RFR: 8339835: Replace usages of -mx and -ms in some client-libs tests

[Jaikiran Pai]

Can I please get a review of this test-only change which updates some client-libs tests to replace the usage of the outdated `-mx` and `-ms` java launcher options with `-Xmx`  and `-Xms`?

As noted in https://bugs.openjdk.org/browse/JDK-8339835, these outdated options will soon be deprecated for removal from the java launcher code.

tier testing in our CI is currently in progress with these changes.

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Commit messages:
 - 8339835: Replace usages of -mx and -ms in some client-libs tests

Changes: https://git.openjdk.org/jdk/pull/20931/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20931&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8339835
  Stats: 21 lines in 11 files changed: 0 ins; 0 del; 21 mod
  Patch: https://git.openjdk.org/jdk/pull/20931.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20931/head:pull/20931

PR: https://git.openjdk.org/jdk/pull/20931