[crac] RFR: Convert CRaC tests from shell scripts to Java [v4]

[Radim Vansa]

> Right now this is a draft as it builds on top of https://github.com/openjdk/crac/pull/47
> 
> Please see `CracTest` javadoc for detailed info.

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

  Address review comments

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

Changes:
  - all: https://git.openjdk.org/crac/pull/50/files
  - new: https://git.openjdk.org/crac/pull/50/files/57e73973..4114106a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=crac&pr=50&range=03
 - incr: https://webrevs.openjdk.org/?repo=crac&pr=50&range=02-03

  Stats: 15 lines in 3 files changed: 3 ins; 4 del; 8 mod
  Patch: https://git.openjdk.org/crac/pull/50.diff
  Fetch: git fetch https://git.openjdk.org/crac pull/50/head:pull/50

PR: https://git.openjdk.org/crac/pull/50