Fix frogsh + Windows + test.dart take 2

tools/testing/dart/test_runner.dart

 // Copyright (c) 2011, 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("test_runner");
 
 #import("status_file_parser.dart");
 #import("test_progress.dart");
 #import("test_suite.dart");
 
@@ skipping 225 matching lines @@
                  testCase.dynamic.compilerArguments,
                  compilerExitHandler);
     } else {
       runCommand(testCase.executablePath, testCase.arguments, exitHandler);
     }
   }
 
   void runCommand(String executable,
                   List<String> arguments,
                   void exitHandler(int exitCode)) {
+    if (new Platform().operatingSystem() == 'windows') {
+      // Windows can't handle the first command if it is a .bat file or the like
+      // with the slashes going the other direction.
+      // TODO(efortuna): Remove this when fixed (Issue 1306).
+      executable = executable.replaceAll('/', '\\');
+    }
     process = new Process.start(executable, arguments);
     process.exitHandler = exitHandler;
     startTime = new Date.now();
     InputStream stdoutStream = process.stdout;
     InputStream stderrStream = process.stderr;
     StringInputStream stdoutStringStream = new StringInputStream(stdoutStream);
     StringInputStream stderrStringStream = new StringInputStream(stderrStream);
     stdoutStringStream.lineHandler =
         makeReadHandler(stdoutStringStream, stdout);
     stderrStringStream.lineHandler =
@@ skipping 287 matching lines @@
           test.displayName != 'dartc/junit_tests') {
         _ensureDartcBatchRunnersStarted(test.executablePath);
         _getDartcBatchRunnerProcess().startTest(test);
       } else {
         new RunningProcess(test).start();
       }
       _numProcesses++;
     }
   }
 }