review request (m): 6330863 InfiniteList.java intermittent timeout

[John Coomes]

I'd appreciate reviews of these changes to fix a corner-case that
can cause test timeouts with parallel old gc.

The review is in two parts; the first part is a prereq that's easily
separated so it's in a separate webrev to make reviews of the real fix
a bit easier.

1) change the PS invoke methods to return an indicator of whether a gc
was done:

	http://cr.openjdk.java.net/~jcoomes/6330863-invoke-return-val/

2) adjust the allocation policy:

	http://cr.openjdk.java.net/~jcoomes/6330863-death-march/

-John