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

tests/compiler/dart2js/type_checker_test.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.
 
 import 'dart:async';
 
 import 'package:async_helper/async_helper.dart';
 import 'package:expect/expect.dart';
 
 import 'package:compiler/src/dart_types.dart';
@@ skipping 2706 matching lines @@
   if (warnings == null) warnings = [];
   if (warnings is! List) warnings = [warnings];
   if (errors == null) errors = [];
   if (errors is! List) errors = [errors];
 
   compiler.diagnosticHandler = createHandler(compiler, text);
 
   Token tokens = scan(text);
   NodeListener listener =
       new NodeListener(const ScannerOptions(), compiler.reporter, null);
-  Parser parser = new Parser(listener, new MockParserOptions());
+  Parser parser = new Parser(listener);
   parser.parseStatement(tokens);
   Node node = listener.popNode();
   Element compilationUnit = new CompilationUnitElementX(
       new Script(null, null, null), compiler.mainApp);
   Element function = new MockElement(compilationUnit);
   TreeElements elements = compiler.resolveNodeStatement(node, function);
   compiler.enqueuer.resolution.emptyDeferredQueueForTesting();
   TypeCheckerVisitor checker =
       new TypeCheckerVisitor(compiler, elements, compiler.types);
   DiagnosticCollector collector = compiler.diagnosticCollector;
@@ skipping 23 matching lines @@
     {warnings, hints}) {
   if (warnings == null) warnings = [];
   if (warnings is! List) warnings = [warnings];
   if (hints == null) hints = [];
   if (hints is! List) hints = [hints];
 
   compiler.resolver.resolve(element);
   Token tokens = scan(text);
   NodeListener listener =
       new NodeListener(const ScannerOptions(), compiler.reporter, null);
-  Parser parser = new Parser(listener, new MockParserOptions(),
+  Parser parser = new Parser(listener,
       asyncAwaitKeywordsEnabled: element.asyncMarker != AsyncMarker.SYNC);
   parser.parseStatement(tokens);
   Node node = listener.popNode();
   TreeElements elements = compiler.resolveNodeStatement(node, element);
   TypeCheckerVisitor checker =
       new TypeCheckerVisitor(compiler, elements, compiler.types);
   DiagnosticCollector collector = compiler.diagnosticCollector;
   collector.clear();
   checker.analyze(node);
   generateOutput(compiler, text);
   compareWarningKinds(text, warnings, collector.warnings);
   compareWarningKinds(text, hints, collector.hints);
 }