[crac] RFR: 8373781: [CRaC] Permit -XX:CPUFeatures on other platforms [v4]

[Radim Vansa]

> Currently `-XX:CPUFeatures` option is available only on `x86_64`. This complicates creating multiarch container images that are meant to be universally runnable (with `-XX:CPUFeatures=generic`).
> 
> I propose to make this option available on all architectures, with the non-arch specific values:
> * `generic`
> * `native`
> * `ignore`
> 
> The implementation on non-x86_64 will only validate the sanity of the value.
> 
> The related option `-XX:+ShowCPUFeatures` will print an informative message (saying that the option does not make much sense).
> 
> `-XX:+IgnoreCPUFeatures` will be permitted as well, but it will be a no-op on the other architectures.

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

  Refine non-Linux behaviour

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

Changes:
  - all: https://git.openjdk.org/crac/pull/282/files
  - new: https://git.openjdk.org/crac/pull/282/files/a58eee1e..e4849639

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=crac&pr=282&range=03
 - incr: https://webrevs.openjdk.org/?repo=crac&pr=282&range=02-03

  Stats: 12 lines in 1 file changed: 9 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/crac/pull/282.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/282/head:pull/282

PR: https://git.openjdk.org/crac/pull/282