Revert "dart2js: Move functionThatReturnsNull to Isolate."

pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart

Index: pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
diff --git a/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart b/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
index 68833dc716efd037c26e396d43efc2ab6df9b989..bb2f2b2aa991b4c9480a7f19d0deb7b313bae4a1 100644
--- a/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
+++ b/pkg/compiler/lib/src/js_emitter/old_emitter/emitter.dart
@@ -733,14 +733,12 @@ class OldEmitter implements Emitter {
   }
 
   jsAst.Statement buildFunctionThatReturnsNull() {
-    return js.statement('#.# = function() {}',
-                        [namer.isolateName,
-                         backend.rti.getFunctionThatReturnsNullName]);
+    return js.statement('# = function() {}',
+                        [backend.rti.getFunctionThatReturnsNullName]);
   }
 
   jsAst.Expression generateFunctionThatReturnsNull() {
-    return js("#.#", [namer.isolateName,
-                      backend.rti.getFunctionThatReturnsNullName]);
+    return js("#", [backend.rti.getFunctionThatReturnsNullName]);
   }
 
   buildMain(jsAst.Statement invokeMain) {