Add --host-checked option to test.dart and use it on dart2js build bots.

dart/tools/testing/dart/test_options.dart

Index: dart/tools/testing/dart/test_options.dart
diff --git a/dart/tools/testing/dart/test_options.dart b/dart/tools/testing/dart/test_options.dart
index e776c598c4bb655dbf030aeb409b34f09ab01082..6a9547839693a1c3f16ac79f3af9486e89056717 100644
--- a/dart/tools/testing/dart/test_options.dart
+++ b/dart/tools/testing/dart/test_options.dart
@@ -119,6 +119,13 @@ Controls how dart code is compiled and executed.
               false,
               'bool'),
           new _TestOptionSpecification(
+              'host_checked',
+              'Run compiler in checked mode',
+              ['--host-checked'],
+              [],
+              false,
+              'bool'),
+          new _TestOptionSpecification(
               'timeout',
               'Timeout in seconds',
               ['-t', '--timeout'],
@@ -386,9 +393,10 @@ Controls how dart code is compiled and executed.
       configuration['progress'] = 'verbose';
     }
 
-    // Create the artificial 'unchecked' option that test status files
+    // Create the artificial 'unchecked' options that test status files
     // expect.
     configuration['unchecked'] = !configuration['checked'];
+    configuration['host_unchecked'] = !configuration['host_checked'];
 
     // Expand the test selectors into a suite name and a simple
     // regular expressions to be used on the full path of a test file
@@ -479,6 +487,9 @@ Controls how dart code is compiled and executed.
           if (configuration['mode'] == 'debug') {
             timeout *= 4;
           }
+          if (configuration['host_checked']) {
+            timeout *= 4;
+          }
           break;
         default:
           if (configuration['mode'] == 'debug') {