RFR (S): Forward-port: 7176220 'Full GC' events miss date stamp information occasionally

[Andreas Eriksson]

Hi,

This fix was actually pushed to jdk7/hsx24 over a year ago by me.
IIRC the push to jdk8/hsx25 was delayed at the time, over fears that it 
would conflict with the big metaspace change and/or JFR work that was 
about to get pushed.
Unfortunately I then forgot all about it.

I would like to push this fix to jdk9 (and then jdk8) now.

Bug: https://bugs.openjdk.java.net/browse/JDK-7176220

Summary:
The problem is that CMS sometimes misses datestamps for time trace 
printouts.
The fix is to move the datestamp print logic into the class that handles 
time trace printouts, GCTraceTime.
This makes it consistent with timestamps, which are already printed from 
there.

Webrev for jdk9:
http://cr.openjdk.java.net/~aeriksso/7176220/webrev.00/

And for reference:
hsx24 review thread: 
http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2013-May/007127.html
hsx24 changeset: 
http://hg.openjdk.java.net/hsx/hsx24/hotspot/rev/aa01d1f5fcd9

Thanks,
Andreas