Revert "Immediately use the generic stub when storing into COW arrays"

Due to unexpected performance implications.

This reverts r10429.

Review URL: https://chromiumcodereview.appspot.com/9150032

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10444 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ic.cc

@@ -1677,9 +1677,6 @@ MaybeObject* KeyedStoreIC::Store(State state,
       if (receiver->elements()->map() ==
           isolate()->heap()->non_strict_arguments_elements_map()) {
         stub = non_strict_arguments_stub();
-      } else if (receiver->elements()->map() ==
-          isolate()->heap()->fixed_cow_array_map()) {
-        // Do nothing, just keep the generic stub.
       } else if (!force_generic) {
         if (key->IsSmi() && (target() != *non_strict_arguments_stub())) {
           StubKind stub_kind = STORE_NO_TRANSITION;