Add support for building patched_sdk and platform.dill for dart2js:

pkg/front_end/lib/src/fasta/parser/dart_vm_native.dart

Index: pkg/front_end/lib/src/fasta/parser/dart_vm_native.dart
diff --git a/pkg/front_end/lib/src/fasta/parser/dart_vm_native.dart b/pkg/front_end/lib/src/fasta/parser/dart_vm_native.dart
index 4c38a81775ac31ecdf99905f7168da769b5d6ffd..6663e3dd264a5e285596bb05f53f929c47fb7a2e 100644
--- a/pkg/front_end/lib/src/fasta/parser/dart_vm_native.dart
+++ b/pkg/front_end/lib/src/fasta/parser/dart_vm_native.dart
@@ -2,7 +2,7 @@
 // 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.
 
-/// Implements support for Dart VM native method bodies on this form:
+/// Implements support for Dart VM native method bodies of this form:
 ///
 ///     native STRING
 ///
@@ -24,7 +24,7 @@ import 'parser.dart' show optional;
 ///
 /// This method is designed to be called when encountering
 /// [ErrorKind.ExpectedBlockToSkip] in [Listener.handleUnrecoverableError].
-Token skipNativeClause(Token token) {
+Token skipVmNativeClause(Token token) {
   if (!optional("native", token)) return null;
   token = token.next;
   if (token.kind != STRING_TOKEN) return null;