Get rid of requested size in RetryAfterGC.

Get rid of requested size in RetryAfterGC.

This was only used by Heap::CollectGarbage to check if after GC
available space is bigger than was requested, but nobody checked
the value returned by Heap::CollectGarbage, so requested size
was efficiently unused.

However, it may trigger spurious out of memory exceptions if requested
size is big enough.

BUG=http://code.google.com/p/chromium/issues/detail?id=54580

Committed: http://code.google.com/p/v8/source/detail?r=5642

[antonm, 2010-10-15 18:25:27]

Mads, Slava,

may you have a look?

[Mads Ager (chromium), 2010-10-18 05:37:36]

LGTM