RFR 8173817: StackOverflowError in "process reaper" thread

[Roger Riggs]

Please review a change to the process reaper completion handler's choice 
of an anonymous inner class
for more consistent stack usage.  Additional background and discussion 
in the issue 8173817 [1].

Webrev:
    http://cr.openjdk.java.net/~rriggs/webrev-stackoverflow-8173817/

Issue:
[1]   https://bugs.openjdk.java.net/browse/JDK-8173817

Thanks, Roger