Add runtime tests for ignored checks

pkg/dev_compiler/test/browser/language_tests.js

 // Copyright (c) 2015, 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.
 
 define(['dart_sdk', 'async_helper', 'expect', 'unittest', 'is', 'require'],
       function(dart_sdk, async_helper, expect, unittest, is, require) {
   'use strict';
 
   async_helper = async_helper.async_helper;
   let minitest = expect.minitest;
@@ skipping 842 matching lines @@
   }
 
   // We run these tests in a mocha test wrapper to avoid the confusing failure
   // case of dart unittests being interleaved with mocha tests.
   // In practice we are really just suppressing all mocha test behavior while
   // Dart unittests run and then re-enabling it when the dart tests complete.
   html_config.useHtmlConfiguration();
   test('run all dart unittests', function(done) { // 'function' to allow `this.timeout`
     // Use the whitelist for all unittests - there may be an error in the framework
     // itself.
-    dart_sdk.dart.ignoreWhitelistedErrors(whitelist);
+    dart_sdk.dart.ignoreWhitelistedErrors(true);
     if (unittest_tests.length == 0) return done();
 
     // TODO(vsm): We're using an old deprecated version of unittest.
     // We need to migrate all tests (in the SDK itself) off of
     // unittest.
 
     // All unittests need to be explicitly marked as such above.  If
     // not, the unittest framework will be run in a 'normal' test and
     // left in an inconsistent state at this point triggering spurious
     // failures.  This check ensures we're not in such a state.  If it fails,
     // we've likely added a new unittest and need to categorize it as such.
     if (unittest.src__test_environment.environment.testCases[dart_sdk.dartx.length] != 0) {
       return done(new Error('Unittest framework in an invalid state'));
     }
 
     this.timeout(100000000);
     this.enableTimeouts(false);
     // Suppress mocha on-error handling because it will mess up unittests.
     window.onerror = function(err, url, line) {
       console.error(err, url, line);
     };
     window.addEventListener('message', (event) => {
       if (event.data == 'unittest-suite-done') {
         window.console.log("Done running unittests");
         let output = document.body.textContent;
         // Restore the Mocha onerror handler in case future tests need to run.
         window.onerror = mochaOnError;
         this.enableTimeouts(true);
+        dart_sdk.dart.ignoreWhitelistedErrors(false);
 
         let numErrors = countMatches(output, /\d\s+ERROR/g);
         let numFails = countMatches(output, /\d\s+FAIL/g);
         if (numErrors != num_expected_unittest_errors ||
             numFails != num_expected_unittest_fails) {
           output = "Expected " + num_expected_unittest_fails +
               " fail and " + num_expected_unittest_errors +
               " error unittests, got " + numFails + " fail and " +
               numErrors + "error tests.\n" + output;
           console.error(output);
           done(new Error(output));
         } else {
           console.log(output);
           done();
         }
       }
     });
 
     for (let action of unittest_tests) {
       try {
         action();
       } catch (e) {
         console.error("Caught error tying to setup test:", e);
       }
     }
   });
 });