RFR: 8222825: ARM32 SIGILL issue on single core CPU (not supported PLDW instruction)

[Boris Ulasevich]

Hi all,

Please review the fix for SIGILL that happens on ARM32 CPU without 
Multiprocessing Extensions support (this applies to single-core arm32 
processors, which are not very common this days). With the fix we check 
PLDW instruction availability on JVM start-up to correct further 
instructions generation.

https://bugs.openjdk.java.net/browse/JDK-8222825
http://cr.openjdk.java.net/~bulasevich/8222825/webrev.03.jdk-jdk

thanks,
Boris