RFR: 7903493: jcstress: Cut down test configurations [v2]

[Aleksey Shipilev]

> Current full jcstress run takes about 60+ days on 36-core machine. This is driven by too many test configurations tested in the default config. We can cut down the test times (again) by re-examining the default run options.

Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:

  Cut down default per test time to 3 seconds

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Changes:
  - all: https://git.openjdk.org/jcstress/pull/142/files
  - new: https://git.openjdk.org/jcstress/pull/142/files/717bb163..3d9875a6

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jcstress&pr=142&range=01
 - incr: https://webrevs.openjdk.org/?repo=jcstress&pr=142&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jcstress/pull/142.diff
  Fetch: git fetch https://git.openjdk.org/jcstress.git pull/142/head:pull/142

PR: https://git.openjdk.org/jcstress/pull/142