Tenure allocation sites only when semi-space is maximum size.

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index 93e247846836423a495bac3848ff1fd4311242f3..06ae55e53e1a17174dfbf3c8aa6ad4d4869c23fa 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -2499,6 +2499,10 @@ class NewSpace : public Space {
     return to_space_.MaximumCapacity();
   }
 
+  bool IsAtMaximumCapacity() {
+    return Capacity() == MaximumCapacity();
+  }
+
   // Returns the initial capacity of a semispace.
   int InitialCapacity() {
     ASSERT(to_space_.InitialCapacity() == from_space_.InitialCapacity());