Remove the ability in dart2js to turn off syntax-only generic methods.

tests/compiler/dart2js/unparser2_test.dart

Index: tests/compiler/dart2js/unparser2_test.dart
diff --git a/tests/compiler/dart2js/unparser2_test.dart b/tests/compiler/dart2js/unparser2_test.dart
index d63bdb49b8add8b8feaa108146749387a252dcfb..820fab7ec91a28cae1d13ce3e2f32398bfd1fc4f 100644
--- a/tests/compiler/dart2js/unparser2_test.dart
+++ b/tests/compiler/dart2js/unparser2_test.dart
@@ -93,7 +93,7 @@ String doUnparse(String source) {
   Token beginToken = scanner.tokenize();
   NodeListener listener =
       new NodeListener(const ScannerOptions(), diagnosticListener, element);
-  Parser parser = new Parser(listener, new MockParserOptions());
+  Parser parser = new Parser(listener);
   parser.parseUnit(beginToken);
   Node node = listener.popNode();
   Expect.isTrue(listener.nodes.isEmpty);