[crac] RFR: Win/Mac build for CRaC [v15]

[Roman Marchenko]

> - OS-dependent CRaC functionality moved to `crac_<os>`.* files.
> - Data structures moved to `crac_structs.hpp`
> - Added necessary cross-platform functionality
> - Some local calls are put under `#ifdef` checks
> - GHA: Enabled Crac tests run in windows build
> - GHA: macOs build is disabled until CRaC moves to newer JDK version.

Roman Marchenko has updated the pull request incrementally with two additional commits since the last revision:

 - Minor change
 - Fixed crac engine dir

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

Changes:
  - all: https://git.openjdk.org/crac/pull/82/files
  - new: https://git.openjdk.org/crac/pull/82/files/cf2cdfeb..b929655e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=crac&pr=82&range=14
 - incr: https://webrevs.openjdk.org/?repo=crac&pr=82&range=13-14

  Stats: 14 lines in 1 file changed: 6 ins; 6 del; 2 mod
  Patch: https://git.openjdk.org/crac/pull/82.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/82/head:pull/82

PR: https://git.openjdk.org/crac/pull/82