Remove hackish way of getting the url for browser testing

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 979 matching lines @@
           // commands will be executed. On subsequent loop iterations, we
           // don't need to do any compilations. Thus we set "commandSet = []".
           commandSet = [];
         }
 
         var htmlPath_subtest = _createUrlPathFromFile(new Path(htmlPath));
         var fullHtmlPath = _getUriForBrowserTest(info, htmlPath_subtest,
                                                  subtestNames, subtestIndex);
 
         List<String> args = <String>[];
+
         if (TestUtils.usesWebDriver(runtime)) {
           args = [
               dartDir.append('tools/testing/run_selenium.py').toNativePath(),
               '--browser=$runtime',
               // NOTE: This value will be overridden by the test runner
               '--timeout=${configuration['timeout']}',
               '--out=$fullHtmlPath'];
           if (runtime == 'dartium') {
             args.add('--executable=$dartiumFilename');
           }
@@ skipping 48 matching lines @@
         } else {
           testCase = new BrowserTestCase(testDisplayName,
               commandSet, configuration, completeHandler, expectations,
               info, info.hasCompileError || info.hasRuntimeError, false);
         }
         if (subtestIndex == 0) {
           multitestParentTest = testCase;
         } else {
           multitestParentTest.addObserver(testCase);
         }
+        testCase.testingUrl = fullHtmlPath;
+
         doTest(testCase);
         subtestIndex++;
       } while(subtestIndex < subtestNames.length);
     }
   }
 
   /** Helper to create a compilation command for a single input file. */
   Command _compileCommand(String inputFile, String outputFile,
       String compiler, String dir, vmOptions, optionsFromFile) {
     String executable = compilerPath;
@@ skipping 851 matching lines @@
  * $pass tests are expected to pass
  * $failOk tests are expected to fail that we won't fix
  * $fail tests are expected to fail that we should fix
  * $crash tests are expected to crash that we should fix
  * $timeout tests are allowed to timeout
  * $compileErrorSkip tests are skipped on browsers due to compile-time error
 """;
     print(report);
    }
 }