RFR: 8288732: Reduce runtime of java.util.concurrent microbenchmarks

[Claes Redestad]

- Refactor so that various baseline micros are not run repeatedly with different parameter values that does not affect the baseline
- Tune iteration times, counts, forks..

Reduces runtime of java.util.concurrent micros from an estimated 14h43m to 1h21m

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Commit messages:
 - Copyrights
 - Merge branch 'master' into micro_runtime_juc
 - Reduce runtime of j.u.concurrent micros

Changes: https://git.openjdk.org/jdk/pull/9214/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9214&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8288732
  Stats: 219 lines in 12 files changed: 117 ins; 21 del; 81 mod
  Patch: https://git.openjdk.org/jdk/pull/9214.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9214/head:pull/9214

PR: https://git.openjdk.org/jdk/pull/9214