Try to let the context disposal GC at idle time have less

impact on the normal idle notification scheme by making sure
we do not restart the idle GC sequence just because of a
forced GC due to context disposal.
Review URL: http://codereview.chromium.org/669150

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4031 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/heap.cc

@@ -3085,6 +3085,7 @@ bool Heap::IdleNotification() {
     HistogramTimerScope scope(&Counters::gc_context);
     CollectAllGarbage(false);
     ASSERT(contexts_disposed_ == 0);
+    last_gc_count = gc_count_;
     return false;
   }