[9] RFR (XS): 6985422: flush the output streams before OnError commands

[Vladimir Ivanov]

http://cr.openjdk.java.net/~vlivanov/6985422/webrev.00/
https://bugs.openjdk.java.net/browse/JDK-6985422

OnError commands are executed before hotspot log is finished.

The fix is to finish the log before executing OnError commands.

Also, I moved compilation replay data dumping logic before OnError 
processing, so compilation replay file is accessible from OnError 
commands as well.

I verified the fix by triggering VM crash w/ -XX:+LogCompilation 
-XX:LogFile=hotspot.log -XX:OnError='cp hotspot.log hs.log' flags and 
checking that hs.log is complete. Without the fix the log is corrupted.

Testing: manual, JPRT.

Thanks!

Best regards,
Vladimir Ivanov