RFR: 8364503: gc/g1/TestCodeCacheUnloadDuringConcCycle.java fails because of race printing to stdout [v2]

[Thomas Schatzl]

> Hi all,
> 
>   please review this change to the `gc/g1/TestCodeCacheUnloadDuringConcCycle.java` test - previously, the GC that we were waiting for in the test could occur between releasing whitebox control and the marker we use to distinguish before/after test setup.
> 
> The change makes sure the marker is printed before releasing Whitebox control. So the concurrent start gc we look for can not happen before the marker printing.
> 
> Testing: passes 5000 runs of that benchmark
> 
> Thanks,
>   Thomas

Thomas Schatzl has updated the pull request incrementally with one additional commit since the last revision:

  * review ayang

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26592/files
  - new: https://git.openjdk.org/jdk/pull/26592/files/fbdc1416..3ff76be7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26592&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26592&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/26592.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26592/head:pull/26592

PR: https://git.openjdk.org/jdk/pull/26592