[crac] RFR: 8364931: [CRaC] Stabilize recompiler tests [v2]

[Timofei Pushkin]

> Stabilizes recompiler tests:
> - `NaturalDecompilationTest` now ensures the method is not enqueued for another compilation before proceeding with the test.
> - In `RecompilationFlagsTest` recompilation waiting period of a predefined length is replaced with waiting for the methods to get enqueued and dequeued to/from the compilation queue.

Timofei Pushkin has updated the pull request incrementally with one additional commit since the last revision:

  Improve assertions in NaturalDecompilationTest

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Changes:
  - all: https://git.openjdk.org/crac/pull/259/files
  - new: https://git.openjdk.org/crac/pull/259/files/09cc0be9..8014e0ea

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=crac&pr=259&range=01
 - incr: https://webrevs.openjdk.org/?repo=crac&pr=259&range=00-01

  Stats: 8 lines in 1 file changed: 0 ins; 3 del; 5 mod
  Patch: https://git.openjdk.org/crac/pull/259.diff
  Fetch: git fetch https://git.openjdk.org/crac.git pull/259/head:pull/259

PR: https://git.openjdk.org/crac/pull/259