Revert "Change dart:io Platform.script to return a Uri."

pkg/scheduled_test/test/metatest.dart

 // Copyright (c) 2013, 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.
 
 /// A test library for testing test libraries? We must go deeper.
 ///
 /// Since unit testing code tends to use a lot of global state, it can be tough
 /// to test. This library manages it by running each test case in a child
 /// isolate, then reporting the results back to the parent isolate.
 library metatest;
@@ skipping 101 matching lines @@
     _testToRun = message['testToRun'];
     _replyTo = message['replyTo'];
     _inChildIsolate = true;
   }
 }
 
 /// Runs the test described by [description] in its own isolate. Returns a map
 /// describing the results of that test run.
 Future<Map> _runInIsolate(String description) {
   var replyPort = new ReceivePort();
-  return Isolate.spawnUri(Platform.script, [], {
+  return Isolate.spawnUri(Uri.parse(Platform.script), [], {
     'testToRun': description,
     'replyTo': replyPort.sendPort
   }).then((_) {
     // TODO(nweiz): Remove this timeout once issue 8417 is fixed and we can
     // capture top-level exceptions.
     return timeout(replyPort.first, 30 * 1000, () {
       throw 'Timed out waiting for test to complete.';
     });
   });
 }
@@ skipping 67 matching lines @@
       "uncaughtError": uncaughtError,
       "results": results.map((testCase) => {
         "description": testCase.description,
         "message": testCase.message,
         "result": testCase.result,
         "stackTrace": testCase.stackTrace
       }).toList()
     });
   }
 }