[build] Split the publish workflow preparation to parallelize slow tests

[simonbasle]

No description provided.

[OlegDokuka]

LGTM

[simonbasle]

in the latest state, splits prepare (which includes shorter tests) vs races tests vs loops tests + jcstress.

the longest is still the races-tagged tests, which run for about 9min on CI.
loops + jcstress run for about 7min.
prepare runs for about 3min.

This PR thus reduces the publish workflow by about 10min (was 19min).

[simonbasle]

@OlegDokuka thanks for the review. Can you double check everything is fine and no testing-related changes are left?

[OlegDokuka]

Some changes to make it working

[OlegDokuka]

Suggested change

	run: ./gradlew test -Pjunit-tags=loops jcstress
	run: ./gradlew test -Pjunit-tags=loops,slow jcstress

[simonbasle]

ok so let me rework this a bit actually. since prepare + base tests + jcstress + loop tests take up about 10min, and race tests take about 9min (on CI), I think we can limit the number of parallel jobs to 2.

[OlegDokuka]

LGTM

[simonbasle]

ok, in the last execution we had:

• prepare (preparation + base tests including loops + jcstress): 8min
• slowChecks (raceXxx tests in CommonPoolTest, tagged "slow"): 10min

I have verified that the test logs show the same number of passed tests (445) by combining the logs of the 2 jobs and comparing to the release's log, filtering on > for test name lines and sorting the result and comparing it just to spot any difference. There is one additional line in the new logs because it outputs 1 STANDARD_OUTPUT line displaying the activated logger in the extra job.