Added the ability to filter which tests are run by name, using a --filter

tools/testing/dart/test_suite.dart

Index: tools/testing/dart/test_suite.dart
===================================================================
--- tools/testing/dart/test_suite.dart	(revision 8995)
+++ tools/testing/dart/test_suite.dart	(working copy)
@@ -446,6 +446,9 @@
       String testPath =
           new File(info.filename).fullPathSync().replaceAll('\\', '/');
       String tempDir = createOutputDirectory(testPath, '');
+      if (configuration['filter'] != '') {
+        args.add('--filter="${configuration["filter"]}"');
+      }
       args.add('--out=$tempDir/out.js');
       List<Command> commands = <Command>[new Command(shellPath(), args)];
       if (configuration['runtime'] == 'd8') {
@@ -454,6 +457,9 @@
       }
       return commands;
     } else {
+      if (configuration['filter'] != '') {
+        args.add('--filter="${configuration["filter"]}"');
+      }
       return <Command>[new Command(shellPath(), args)];
     }
   }
@@ -563,7 +569,8 @@
         File file = new File(dartWrapperFilename);
         RandomAccessFile dartWrapper = file.openSync(FileMode.WRITE);
         dartWrapper.writeStringSync(
-            DartTestWrapper(dartDir, dartLibraryFilename));
+            DartTestWrapper(dartDir, dartLibraryFilename,
+                configuration['filter']));
         dartWrapper.closeSync();
       } else {
         dartWrapperFilename = testPath;