RFR: 8290391: Reduce runtime of java.util package microbenchmarks [v2]

[Eric Caspole]

> Adds Warmup, Measurement and Fork annotations to reduce the run time from 1 day 16 hours to 8 hours for this set.

Eric Caspole has updated the pull request incrementally with one additional commit since the last revision:

  Apply @cl4es comments

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9523/files
  - new: https://git.openjdk.org/jdk/pull/9523/files/8d71eb4e..50028d59

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9523&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9523&range=00-01

  Stats: 9 lines in 3 files changed: 3 ins; 3 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/9523.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9523/head:pull/9523

PR: https://git.openjdk.org/jdk/pull/9523