RFR: 7903781: Report the process id of the agent or other VM that was used for a jtreg action [v2]

[Jaikiran Pai]

> Can I please get a review of this change which proposes to repor the process id of the process that was used to run a jtreg action? This change addresses https://bugs.openjdk.org/browse/CODETOOLS-7903781.
> 
> As noted in that linked enhancement request, this change will report the process id  the `section` messages of each action. This will now look like:
> 
> 
> #section:compile
> ----------messages:(7/297)----------
> command: compile test/streams/FileDescriptorTest.java
> reason: .class file out of date or does not exist
> started: Fri Jul 26 00:56:01 UTC 2024
> Mode: othervm
> Process id: 88469
> finished: Fri Jul 26 00:56:01 UTC 2024
> elapsed time (seconds): 0.254
> 
> ....
> 
> #section:main
> ----------messages:(7/232)----------
> command: main FileDescriptorTest
> reason: User specified action: run main FileDescriptorTest 
> started: Fri Jul 26 00:56:01 UTC 2024
> Mode: othervm
> Process id: 88470
> finished: Fri Jul 26 00:56:01 UTC 2024
> elapsed time (seconds): 0.042
> 
> Notice the new "Process id: ..." line in those sections.

Jaikiran Pai has updated the pull request incrementally with one additional commit since the last revision:

  include a self test for verifying the process id in the generated report

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

Changes:
  - all: https://git.openjdk.org/jtreg/pull/215/files
  - new: https://git.openjdk.org/jtreg/pull/215/files/02b61ded..7404620f

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jtreg&pr=215&range=01
 - incr: https://webrevs.openjdk.org/?repo=jtreg&pr=215&range=00-01

  Stats: 42 lines in 3 files changed: 40 ins; 1 del; 1 mod
  Patch: https://git.openjdk.org/jtreg/pull/215.diff
  Fetch: git fetch https://git.openjdk.org/jtreg.git pull/215/head:pull/215

PR: https://git.openjdk.org/jtreg/pull/215