RFR: 8327246: Add a jcmd diagnostic command to list the jar files loaded by a process [v12]

[Larry Cable]

> modified the pre-existing VM.classes jcmd to add a 'location' option, that when specified, will (natively) attempt to obtain the value (if non-null) of the location URL of the CodeSource of each classes ProtectionDomain.
> 
> effectively:
> 
> someObject.getClass().getProtectionDomain().getCodeSource().getLocation().toExternalForm()
> 
> (where interim oops are null-checked)

Larry Cable has updated the pull request incrementally with one additional commit since the last revision:

  JDK-8327246: updated VM.classes description as per previous changes to -help text

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/29048/files
  - new: https://git.openjdk.org/jdk/pull/29048/files/f2198458..4b1bb228

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=29048&range=11
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=29048&range=10-11

  Stats: 6 lines in 1 file changed: 3 ins; 1 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/29048.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29048/head:pull/29048

PR: https://git.openjdk.org/jdk/pull/29048