Remove reference to ObjectNotClosureException in dart2js.

lib/compiler/implementation/lib/js_helper.dart

Index: lib/compiler/implementation/lib/js_helper.dart
diff --git a/lib/compiler/implementation/lib/js_helper.dart b/lib/compiler/implementation/lib/js_helper.dart
index a961599608584f2ed9c6f2226afca6ad0a82006d..8f938e4d4f9205780b28cf73579054123c53f230 100644
--- a/lib/compiler/implementation/lib/js_helper.dart
+++ b/lib/compiler/implementation/lib/js_helper.dart
@@ -882,17 +882,9 @@ unwrapException(ex) {
         type == 'called_non_callable' ||
         type == 'non_object_property_call' ||
         type == 'non_object_property_load') {
-      if (name is String && name.startsWith(r'call$')) {
-        return new ObjectNotClosureException();
-      } else {
-        return new NullPointerException();
-      }
+      return new NullPointerException();
     } else if (type == 'undefined_method') {
-      if (name is String && name.startsWith(r'call$')) {
-        return new ObjectNotClosureException();
-      } else {
-        return new NoSuchMethodError('', name, []);
-      }
+      return new NoSuchMethodError('', name, []);
     }
 
     var ieErrorCode = JS('int', '#.number & 0xffff', ex);