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

pkg/front_end/tool/fasta_perf.dart

 // Copyright (c) 2017, 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.
 
 /// An entrypoint used to run portions of fasta and measure its performance.
 library front_end.tool.fasta_perf;
 
 import 'dart:async';
 import 'dart:io';
 
@@ skipping 188 matching lines @@
 // Invoke the fasta kernel generator for the program starting in [entryUri]
 // TODO(sigmund): update to uyse the frontend api once fasta is beind hit.
 generateKernel(Uri entryUri,
     {bool compileSdk: true, bool strongMode: false}) async {
   // TODO(sigmund): this is here only to compute the input size,
   // we should extract the input size from the frontend instead.
   scanReachableFiles(entryUri);
 
   var timer = new Stopwatch()..start();
   final Ticker ticker = new Ticker();
-  final DillTarget dillTarget = new DillTarget(ticker, uriResolver);
+  final DillTarget dillTarget = new DillTarget(ticker, uriResolver, false);
   final KernelTarget kernelTarget =
-      new KernelTarget(dillTarget, uriResolver, strongMode);
+      new KernelTarget(dillTarget, uriResolver, strongMode, false);
   var entrypoints = [
     entryUri,
     // These extra libraries are added to match the same set of libraries
     // scanned by default by the VM and the other benchmarks.
     Uri.parse('dart:async'),
     Uri.parse('dart:collection'),
     Uri.parse('dart:convert'),
     Uri.parse('dart:core'),
     Uri.parse('dart:developer'),
     Uri.parse('dart:_internal'),
@@ skipping 23 matching lines @@
 /// Report that metric [name] took [time] micro-seconds to process
 /// [inputSize] characters.
 void report(String name, int time) {
   var sb = new StringBuffer();
   var padding = ' ' * (20 - name.length);
   sb.write('$name:$padding $time us, ${time ~/ 1000} ms');
   var invSpeed = (time * 1000 / inputSize).toStringAsFixed(2);
   sb.write(', $invSpeed ns/char');
   print('$sb');
 }