RFR: 7903448: JMH: Override the use of compiler hints using a system property [v3]

[Gilles Duboscq]

> Using `-Djmh.compilerhints.mode=true` will force the use of compiler hints. `-Djmh.compilerhints.mode=false` will prevent the use of compiler hints. When the system property is not set, the current beahviour based on vm name and version will be used by default.
> 
> This is especially useful when working with uncommon / rare JVMs or when adding compiler hints support to a new JVM.
> 
> I considered auto-detecting support for compiler hints but that didn't fit very well in the current code and required much more intrusive changes.

Gilles Duboscq has updated the pull request incrementally with one additional commit since the last revision:

  Split CompilerHintsSelect.AUTO into AUTO_ON/AUTO_OFF
  
  Only print compiler hints status when it is forced

-------------

Changes:
  - all: https://git.openjdk.org/jmh/pull/96/files
  - new: https://git.openjdk.org/jmh/pull/96/files/5e550e44..9c1617af

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmh&pr=96&range=02
 - incr: https://webrevs.openjdk.org/?repo=jmh&pr=96&range=01-02

  Stats: 67 lines in 2 files changed: 37 ins; 9 del; 21 mod
  Patch: https://git.openjdk.org/jmh/pull/96.diff
  Fetch: git fetch https://git.openjdk.org/jmh.git pull/96/head:pull/96

PR: https://git.openjdk.org/jmh/pull/96