Simplify parsing of 'new' operator.

tests/language/src/Factory2NegativeTest.dart

+// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test compile time error for factories with parameterized types.
+
+interface Link<T> default LinkFactory {
+  Link.create();
+}
+
+class LinkFactory {   // Compile time error: should be LinkFactory<T> to match interface above
+  factory Link.create() {
+    return null;
+  }
+}
+
+main() {
+  var a = new Link.create();  // Equivalent to new Link<Dynamic>.create().
+}