[7u4] Request for approval for CR 7091003 ScheduledExecutorService never executes Runnable with corePoolSize of zero

[Chris Hegarty]

This is a request to push the following fix to 
http://hg.openjdk.java.net/jdk7u/jdk7u-dev/jdk/

CR 7091003: ScheduledExecutorService never executes Runnable with 
corePoolSize of zero
   http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7091003

The changes are identical to jdk8.
   http://hg.openjdk.java.net/jdk8/tl/jdk/rev/8dab38c07b6b

Thanks,
-Chris.