[Object.observe] Don't force normalization of elements for observed objects

src/ia32/stub-cache-ia32.cc

Index: src/ia32/stub-cache-ia32.cc
diff --git a/src/ia32/stub-cache-ia32.cc b/src/ia32/stub-cache-ia32.cc
index 23e2398b34657d6efbd0f25f7a99bd026de21925..dc8c20ea1f8dc0cf402d72bf115cb7f046be3e60 100644
--- a/src/ia32/stub-cache-ia32.cc
+++ b/src/ia32/stub-cache-ia32.cc
@@ -1737,8 +1737,10 @@ Handle<Code> CallStubCompiler::CompileArrayPushCall(
   //  -- esp[(argc + 1) * 4] : receiver
   // -----------------------------------
 
-  // If object is not an array, bail out to regular call.
-  if (!object->IsJSArray() || !cell.is_null()) {
+  // If object is not an array or is observed, bail out to regular call.
+  if (!object->IsJSArray() ||
+      !cell.is_null() ||
+      Handle<JSArray>::cast(object)->map()->is_observed()) {
     return Handle<Code>::null();
   }
 
@@ -1996,8 +1998,10 @@ Handle<Code> CallStubCompiler::CompileArrayPopCall(
   //  -- esp[(argc + 1) * 4] : receiver
   // -----------------------------------
 
-  // If object is not an array, bail out to regular call.
-  if (!object->IsJSArray() || !cell.is_null()) {
+  // If object is not an array or is observed, bail out to regular call.
+  if (!object->IsJSArray() ||
+      !cell.is_null() ||
+      Handle<JSArray>::cast(object)->map()->is_observed()) {
     return Handle<Code>::null();
   }