Revert "Move dart2js from sdk/lib/_internal/compiler to pkg/compiler"

pkg/compiler/lib/src/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;
-
-const ITERATIONS_FLAG_PREFIX = "--iterations=";
-void main(List<String> args) {
-  print("Reminder: for best performance, "
-        "dart2js should be run with the VM flag --heap_growth_rate=512");
-  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 '$ITERATIONS_FLAG_PREFIX<count>' to set a repetition count"
-          " (as first flag).");
-  }
-  args = ["--suppress-warnings", "--suppress-hints"]..addAll(args);
-  void iterate() {
-    count++;
-    sw.reset();
-    sw.start();
-    dart2js.internalMain(args)
-      .then((_) {
-        print("$count: ${sw.elapsedMilliseconds}ms");
-      })
-      .then((_) {
-        if (maxCount == null || count < maxCount) {
-          iterate();
-        }
-      });
-  }
-  iterate();
-}