RFR: 8288667: Reduce runtime of java.text microbenchmarks

[Claes Redestad]

- Refactor micro using a range of parameters to a simpler benchmark that tests different values in one pass
- Reduce iterations and their runtimes, but add forks (important to be able to detect run-to-run variation anomalies)

Just one micro modified in this package, but reduces total runtime from 16 minutes to ~1 minute

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Commit messages:
 - Reduce runtime of java.text micros

Changes: https://git.openjdk.org/jdk/pull/9198/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9198&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8288667
  Stats: 21 lines in 1 file changed: 10 ins; 2 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/9198.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9198/head:pull/9198

PR: https://git.openjdk.org/jdk/pull/9198