[crac] RFR: 8375044: [CRaC] Structured engine options info [v7]

[Radim Vansa]

> Currently the engine documents all exposed options through the description extension; this has some downsides:
> 
> * when the JVM wants to change engine option default, -XX:CRaCEngineOptions=help would print wrong value
> * options completely controlled by JVM (such as image_location) are reported, too
> * options documentation format is fully up to the engine (and it would be more complicated to reflow lines in the output)
> 
> The solution is exposing options info in a more structured manner.
> 
> As an extra feature we can use -XX:CRaCEngineOptions=help=foo to limit help to only those containing 'foo' in the name.

Radim Vansa has updated the pull request incrementally with one additional commit since the last revision:

  Apply suggestions from code review
  
  Move _options intitialization
  
  Co-authored-by: Timofei Pushkin <pushkin.td at gmail.com>

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

Changes:
  - all: https://git.openjdk.org/crac/pull/286/files
  - new: https://git.openjdk.org/crac/pull/286/files/49407b6c..b4e1cb4a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=crac&pr=286&range=06
 - incr: https://webrevs.openjdk.org/?repo=crac&pr=286&range=05-06

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/crac/pull/286.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/286/head:pull/286

PR: https://git.openjdk.org/crac/pull/286