Upload new Dart binaries and re-enable unit tests for test scripts.

tools/testing/dart/multitest.dart

Index: tools/testing/dart/multitest.dart
diff --git a/tools/testing/dart/multitest.dart b/tools/testing/dart/multitest.dart
index e2b6aeec217560b1250de3ef22c9a742ee19247f..abc4441992f5da124c5f101e98e99538540581e4 100644
--- a/tools/testing/dart/multitest.dart
+++ b/tools/testing/dart/multitest.dart
@@ -216,7 +216,7 @@ Future doMultitest(Path filePath, String outputDir, Path suiteDir,
   }
 
   // Wait until all imports are copied before scheduling test cases.
-  return Futures.wait(futureCopies).then((_) {
+  return Future.wait(futureCopies).then((_) {
     String baseFilename = filePath.filenameWithoutExtension;
     for (String key in tests.keys) {
       final Path multitestFilename =
@@ -266,5 +266,5 @@ Path CreateMultitestDirectory(String outputDir, Path suiteDir) {
   if (!dir.existsSync()) {
     dir.createSync();
   }
-  return new Path.fromNative(new File(path).fullPathSync());
+  return new Path(new File(path).fullPathSync());
 }