Fix https://code.google.com/p/dart/issues/detail?id=15132, by not doing load elimination on typed a…

sdk/lib/_internal/compiler/implementation/js_backend/backend.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/js_backend/backend.dart	(revision 30337)
+++ sdk/lib/_internal/compiler/implementation/js_backend/backend.dart	(working copy)
@@ -1832,6 +1832,13 @@
         && mask.satisfies(jsIndexingBehaviorInterface, compiler);
   }
 
+  bool couldBeTypedArray(TypeMask mask) {
+    TypeMask indexing = new TypeMask.subtype(jsIndexingBehaviorInterface);
+    // Checking if [mask] contains [indexing] means that we want to
+    // know if [mask] is not a more specific type than [indexing].
+    return isTypedArray(mask) || mask.containsMask(indexing, compiler);
+  }
+
   /// Called when [enqueuer] is empty, but before it is closed.
   void onQueueEmpty(Enqueuer enqueuer) {
     if (!enqueuer.isResolutionQueue && preMirrorsMethodCount == 0) {