RFR(XS): 8010227: Remove promotion failed from young collection event

[Jesper Wilhelmsson]

Could I have a couple of reviews for this really small change?

Bug 8010227: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8010227

The young garbage collection tracing event has a boolean to indicate if a 
promotion failed has occurred or not. This information is also available in its 
own event so the variable is duplicating the information. It was introduced for 
convenience to make it easy to see if a collection got promotion failed or not 
when looking at the GC events. However, the existence of this variable 
complicates the implementation of the evacuation failed event for G1, so we have 
decided to remove it.

Webrev: http://cr.openjdk.java.net/~jwilhelm/8010227/webrev/

Thanks,
/Jesper