Code cleanup: moving compiler perf tests to compiler/tool

pkg/compiler/tool/dart2js_stress.dart

 // Copyright (c) 2014, 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.stress;
 
-import "dart2js.dart" as dart2js;
+import 'package:compiler/src/dart2js.dart' as dart2js;
+import 'dart:io' show Platform;
 
 const ITERATIONS_FLAG_PREFIX = "--iterations=";
 void main(List<String> args) {
   Stopwatch sw = new Stopwatch();
   int count = 0;
   int maxCount = null;
   if (args.isNotEmpty && args[0].startsWith(ITERATIONS_FLAG_PREFIX)) {
     maxCount = int.parse(args[0].substring(ITERATIONS_FLAG_PREFIX.length));
     args = args.sublist(1);
   }
   if (maxCount == null) {
     print("Running indefinitely.\n"
         "Use '$ITERATIONS_FLAG_PREFIX<count>' to set a repetition count"
         " (as first flag).");
   }
-  args = ["--suppress-warnings", "--suppress-hints"]..addAll(args);
+  args = ["--suppress-warnings", "--suppress-hints", "--library-root="
+      "${Platform.script.resolve('../../../sdk').toFilePath()}"]
+           ..addAll(args);
   void iterate() {
     count++;
     sw.reset();
     sw.start();
     dart2js.internalMain(args).then((_) {
       print("$count: ${sw.elapsedMilliseconds}ms");
     }).then((_) {
       if (maxCount == null || count < maxCount) {
         iterate();
       }
     });
   }
 
   iterate();
 }