Make standalone tests not dependent on current working directory.

tools/testing/dart/test_suite.dart

 // Copyright (c) 2012, 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.
 
 /**
  * Classes and methods for enumerating and preparing tests.
  *
  * This library includes:
  *
  * - Creating tests by listing all the Dart files in certain directories,
@@ skipping 1533 matching lines @@
         configuration["compiler"] == "dart2analyzer") &&
         (filePath.filename.contains("dart2js") ||
         filePath.directoryPath.segments().last.contains('html_common'))) {
       args.add("--use-dart2js-libraries");
     }
 
     bool isMultitest = optionsFromFile["isMultitest"];
     List<String> dartOptions = optionsFromFile["dartOptions"];
 
     assert(!isMultitest || dartOptions == null);
-    if (dartOptions == null) {
-      args.add(filePath.toNativePath());
-    } else {
-      var executable_name = dartOptions[0];
-      // TODO(ager): Get rid of this hack when the runtime checkout goes away.
-      var file = new File(executable_name);
-      if (!file.existsSync()) {
-        executable_name = '../$executable_name';
-        assert(new File(executable_name).existsSync());
-        dartOptions[0] = executable_name;
-      }
+    args.add(filePath.toNativePath());
+    if (dartOptions != null) {
       args.addAll(dartOptions);
     }
 
     return args;
   }
 
   String packageRoot(String packageRootFromFile) {
     if (packageRootFromFile == "none") {
       return null;
     }
@@ skipping 822 matching lines @@
       for (var key in PATH_REPLACEMENTS.keys) {
         if (path.startsWith(key)) {
           path = path.replaceFirst(key, PATH_REPLACEMENTS[key]);
           break;
         }
       }
     }
     return path;
   }
 }