RFR: 8314828: Mark 3 jcmd comman-line options test as vm.flagless

[Leonid Mesnik]

Mark 3 tests as flagless to don't run them if not needed. Also, small clean up.

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Commit messages:
 - Merge branch 'master' of https://github.com/openjdk/jdk into 8314828
 - 8314828: Mark 3 jcmd comman-line options test as vm.flagless

Changes: https://git.openjdk.org/jdk/pull/15407/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15407&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8314828
  Stats: 6 lines in 3 files changed: 0 ins; 1 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/15407.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15407/head:pull/15407

PR: https://git.openjdk.org/jdk/pull/15407