Fix for issue r1469: DartVM appears to not GC closure reachable memory properly

Fix for issue r1469: DartVM appears to not GC closure reachable memory properly

(The issue was diagnosed and solved by Siva)

The problem appears when allocating large arrays that are stored in a context.
We allocate large arrays directly in the old space. The context in which these arrays are stored is in the new space. When we do an old gen GC we were not first scavenging the new space. As a result the large arrays still remained when we did the old-gen GC, resulting in OOM.

The fix is to do both a new gen scavenge and an old gen mark-sweep when we run out of space in the old gen.
Committed: https://code.google.com/p/dart/source/detail?r=3856

[siva, 2012-02-02 17:41:02]

lgtm