RFR: 8332124: Jcmd processing should accept the "help" sub option as command argument [v4]

[Sonia Zaldana Calles]

> Hi all, 
> 
> This PR addresses [8332124](https://bugs.openjdk.org/browse/JDK-8332124) enabling jcmd to accept "help" as an argument to subcommands. 
> 
> Testing: 
> - [x] Verified running `jcmd 4711 VM.metaspace help` works along with other subcommands. 
> - [x] Added test case passes. 
> 
> Thanks, 
> Sonia

Sonia Zaldana Calles has updated the pull request incrementally with one additional commit since the last revision:

  Enabling only -h or --help. Also modifying test case

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/19776/files
  - new: https://git.openjdk.org/jdk/pull/19776/files/74a563ae..65cab4d3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19776&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19776&range=02-03

  Stats: 27 lines in 3 files changed: 13 ins; 3 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/19776.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19776/head:pull/19776

PR: https://git.openjdk.org/jdk/pull/19776