Attempt to fix Windows path issue.

tests/standalone/io/file_test.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.
 //
 // Dart test program for testing file I/O.
 
 // OtherResources=fixed_length_file
 // OtherResources=read_as_text.dat
 // OtherResources=readline_test1.dat
 
@@ skipping 1388 matching lines @@
       brokenLink.createSync(dest);
       Expect.throws(() => file.renameSync('xxx'));
       brokenLink.deleteSync();
     }
   }
 
   // Helper method to be able to run the test from the runtime
   // directory, or the top directory.
   static String getFilename(String path) {
     var testPath = Platform.script.resolve(path);
-    return new File.fromUri(testPath).existsSync()
-        ? testPath.toFilePath()
-        : Uri.parse(Platform.executable).resolve('../../runtime/$path').toFilePath();
+    if (new File.fromUri(testPath).existsSync()) {
+      return testPath.toFilePath();
+    }
+    return Uri.parse(Platform.resolvedExecutable)
+              .resolve('../../runtime/$path').toFilePath();
   }
 
   // Main test entrypoint.
   static testMain() {
     asyncStart();
 
     testRead();
     testReadSync();
     testReadStream();
     testLengthSync();
@@ skipping 49 matching lines @@
       testLastModified();
       testDoubleAsyncOperation();
       asyncEnd();
     });
   }
 }
 
 main() {
   FileTest.testMain();
 }