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

tools/testing/dart/test_suite.dart

Index: tools/testing/dart/test_suite.dart
diff --git a/tools/testing/dart/test_suite.dart b/tools/testing/dart/test_suite.dart
index 4ea2d1641c4d1367b6da818be02e615ce71f9273..c918b7738b9876fe70b0ebedcc5fd32b315e5a67 100644
--- a/tools/testing/dart/test_suite.dart
+++ b/tools/testing/dart/test_suite.dart
@@ -988,7 +988,7 @@ class StandardTestSuite extends TestSuite {
         // 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));