(XS) RFR: 8131045: Obsolete JNIDetachReleasesMonitors

[David Holmes]

bug: https://bugs.openjdk.java.net/browse/JDK-8131045

webrev: http://cr.openjdk.java.net/~dholmes/8131045/webrev/

The JNIDetachReleasesMonitors flag was added to JDK 6 when it was 
realized that the VM was not compliant with the JNI specification 
regarding the release of monitors when a JNI attached thread detached - 
see JDK-6336479. The flag allowed for restoration of the incorrect 
behaviour if an application was somehow relying on it.

By now all applications should themselves be JNI-spec compliant and this 
workaround should not be needed, so we can obsolete the 
JNIDetachReleasesMonitors flag in JDK 9 (accept it, report it, but take 
no action) and expire (remove) it in JDK 10.

 > ./b00/linux-i586-internal/images/jdk/bin/java 
-XX:-JNIDetachReleasesMonitors -version
Java HotSpot(TM) Server VM warning: Ignoring option 
JNIDetachReleasesMonitors; support was removed in 9.0

Testing: JPRT

I haven't yet found any tests that involve this flag but there's bound 
to be at least one hiding somewhere. :)

A CCC request has been filed.

Thanks,
David