RFR: 8311946: add support for libgraal specific jtreg tests [v5]

[Doug Simon]

> This PR adds support for `jdk.hasLibgraal` and `vm.libgraal.enabled` properties that can be used with the jtreg `@requires` tag to determine if a libgraal specific test should run.
> 
> * `jdk.hasLibgraal`: the libgraal shared library file is present
> * `vm.libgraal.enabled`: libgraal is used as JIT compiler

Doug Simon has updated the pull request incrementally with one additional commit since the last revision:

  fix spelling

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/14851/files
  - new: https://git.openjdk.org/jdk/pull/14851/files/05760ec3..1fe7a305

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14851&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14851&range=03-04

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/14851.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14851/head:pull/14851

PR: https://git.openjdk.org/jdk/pull/14851