RFR: 8141330: [JVMCI] avoid deadlock between application thread and JVMCI compiler thread under -Xbatch

[Doug Simon]

This change passes JPRT.

> On 10 Nov 2015, at 09:05, Doug Simon <doug.simon at oracle.com> wrote:
> 
> Please review this change that addresses a deadlock between an application thread and a JVMCI compiler thread when blocking compilation (i.e., -Xbatch) is enabled. The deadlock can occur when an application thread acquires a lock (typically related to class loading) and then triggers a blocking JVMCI compilation where the JVMCI compiler thread subsequently tries to acquire the same lock.
> 
> http://cr.openjdk.java.net/~dnsimon/8141330/
> https://bugs.openjdk.java.net/browse/JDK-8141330
> 
> -Doug