Improve hot reload test mode

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 285 matching lines @@
     }
     // Test if the selector includes this test.
     RegExp pattern = configuration['selectors'][suiteName];
     if (!pattern.hasMatch(testCase.displayName)) {
       return;
     }
 
     if (configuration['hot_reload']) {
       // Handle reload special cases.
       if (expectations.contains(Expectation.COMPILETIME_ERROR)) {
-        // Skip reloading tests with expected compilation errors.
+        // Running a test that expects a compilation error with hot reloading
+        // is redundant with a regular run of the test.
         return;
       }
     }
 
     // Update Summary report
     if (configuration['report']) {
       if (testCase.expectCompileError &&
           TestUtils.isBrowserRuntime(configuration['runtime']) &&
           new CompilerConfiguration(configuration).hasCompiler) {
         summaryReport.addCompileErrorSkipTest();
@@ skipping 521 matching lines @@
       enqueueTestCaseFromTestInformation(info);
       return;
     }
     if (!isTestFile(filename)) return;
     Path filePath = new Path(filename);
 
     var optionsFromFile = readOptionsFromFile(filePath);
     CreateTest createTestCase = makeTestCaseCreator(optionsFromFile);
 
     if (optionsFromFile['isMultitest']) {
-      group.add(doMultitest(filePath, buildDir, suiteDir, createTestCase));
+      group.add(doMultitest(filePath,
+                            buildDir,
+                            suiteDir,
+                            createTestCase,
+                            configuration['hot_reload']));
     } else {
       createTestCase(filePath, filePath, optionsFromFile['hasCompileError'],
           optionsFromFile['hasRuntimeError'],
           hasStaticWarning: optionsFromFile['hasStaticWarning']);
     }
   }
 
   static Path _findPubspecYamlFile(Path filePath) {
     final existsCache = TestUtils.existsCache;
 
@@ skipping 1619 matching lines @@
       }
       if (path.length > WINDOWS_SHORTEN_PATH_LIMIT) {
         ++shortNameCounter;
         var pathEnd = path.substring(path.length - WINDOWS_PATH_END_LENGTH);
         path = "short${shortNameCounter}_$pathEnd";
       }
     }
     return path;
   }
 }