RFR [8055338]: (process) Add instrumentation to help diagnose JDK-6573254

[Ivan Gerasimov]

Hello!

This is a request to temporarily add some instrumentation code to 
hotspot to help diagnose the intermittent failure on Windows, which 
results in a wrong exit code of (sub-)process.

BUGURL: https://bugs.openjdk.java.net/browse/JDK-8055338
WEBREV: http://cr.openjdk.java.net/~igerasim/8055338/0/webrev/

Sincerely yours,
Ivan