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

pkg/compiler/lib/src/parser/partial_elements.dart

 // Copyright (c) 2015, 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.
 
 library dart2js.parser.partial_elements;
 
 import '../common.dart';
 import '../common/resolution.dart' show ParsingContext, Resolution;
 import '../dart_types.dart' show DynamicType;
 import '../elements/elements.dart'
@@ skipping 356 matching lines @@
     return cachedNode;
   }
 
   ClassNode parseNode(ParsingContext parsing) {
     if (cachedNode != null) return cachedNode;
     DiagnosticReporter reporter = parsing.reporter;
     reporter.withCurrentElement(this, () {
       parsing.measure(() {
         MemberListener listener = new MemberListener(
             parsing.getScannerOptionsFor(this), reporter, this);
-        Parser parser = new ClassElementParser(listener, parsing.parserOptions);
+        Parser parser = new ClassElementParser(listener);
         try {
           Token token = parser.parseTopLevelDeclaration(beginToken);
           assert(identical(token, endToken.next));
           cachedNode = listener.popNode();
           assert(invariant(beginToken, listener.nodes.isEmpty,
               message: "Non-empty listener stack: ${listener.nodes}"));
         } on ParserError {
           // TODO(ahe): Often, a ParserError is thrown while parsing the class
           // body. This means that the stack actually contains most of the
           // information synthesized below. Consider rewriting the parser so
@@ skipping 45 matching lines @@
   return parsing.measure(() {
     return reporter.withCurrentElement(element, () {
       CompilationUnitElement unit = element.compilationUnit;
       NodeListener listener = new NodeListener(
           parsing.getScannerOptionsFor(element), reporter, unit);
       listener.memberErrors = listener.memberErrors.prepend(false);
       try {
         if (partial.hasParseError) {
           listener.suppressParseErrors = true;
         }
-        doParse(new Parser(listener, parsing.parserOptions));
+        doParse(new Parser(listener));
       } on ParserError catch (e) {
         partial.hasParseError = true;
         return new ErrorNode(element.position, e.reason);
       }
       Node node = listener.popNode();
       assert(listener.nodes.isEmpty);
       return node;
     });
   });
 }