Practically remove boot.js, adds the initialization from the Dart side of

tools/testing/dart/test_suite.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
@@ skipping 970 matching lines @@
       // Construct the command(s) that compile all the inputs needed by the
       // browser test. For running Dart in DRT, this will be noop commands.
       List<Command> commands = [];
 
       // Use existing HTML document if available.
       String htmlPath;
       if (customHtml.existsSync()) {
         // If necessary, run the Polymer deploy steps.
         // TODO(jmesserly): this should be generalized for any tests that
         // require Pub deploy, not just polymer.
-        if (customHtml.readAsStringSync().contains('polymer/boot.js')) {
+        if (customHtml.readAsStringSync().contains('polymer/init.dart')) {
           if (compiler != 'none') {
             commands.add(_polymerDeployCommand(
                 customHtmlPath, tempDir, optionsFromFile));
 
             htmlPath = '$tempDir/test/$nameNoExt.html';
             dartWrapperFilename = '${htmlPath}_bootstrap.dart';
             compiledDartWrapperFilename = '$dartWrapperFilename.js';
           } else {
             htmlPath = customHtmlPath;
           }
@@ skipping 1037 matching lines @@
  * $pass tests are expected to pass
  * $failOk tests are expected to fail that we won't fix
  * $fail tests are expected to fail that we should fix
  * $crash tests are expected to crash that we should fix
  * $timeout tests are allowed to timeout
  * $compileErrorSkip tests are skipped on browsers due to compile-time error
 """;
     print(report);
    }
 }