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

[Gilles Duboscq]

On Tue, 7 Mar 2023 16:37:01 GMT, Gilles Duboscq <gdub at openjdk.org> wrote:

> 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.

I have changed the `jmh.compilerhints.mode` system property to access the 3 suggested values and implemented it following the implementation of the blackhole modes.

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

PR Comment: https://git.openjdk.org/jmh/pull/96#issuecomment-1481715589