since the incremental visitor is setting the gc_age fields correctly.
This means the ResetSharedFunctionInfoCountersDuringIncrementalMarking
test passes even if it hits a marking stack overflow.
Review URL: https://chromiumcodereview.appspot.com/10258001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11481 ce2b1a6d-e550-0410-aec6-3dcde31c8c00