Bug 850749 - Make Cell::isTenured use the new IsInsideNursery; r=billm

--HG--
extra : rebase_source : 7a7e78012fac6ae26a2033c2c71a8f9d4a00b088

js/src/jsgc.cpp

@@ -286,7 +286,7 @@ ArenaHeader::checkSynchronizedWithFreeList() const
 bool
 js::gc::Cell::isTenured() const
 {
-    return true;
+    return !IsInsideNursery(runtime(), this);
 }
 #endif