Fixed skipping_dart2js_compilations_test after changing Command() constructor

tests/standalone/io/test_runner_test.dart

Index: tests/standalone/io/test_runner_test.dart
diff --git a/tests/standalone/io/test_runner_test.dart b/tests/standalone/io/test_runner_test.dart
index 79a8522d1605892d3f31cce0892d77262cbe6b31..d07558aaec936a88ad422bce429c2989a63c30ef 100644
--- a/tests/standalone/io/test_runner_test.dart
+++ b/tests/standalone/io/test_runner_test.dart
@@ -71,13 +71,15 @@ class CustomTestSuite extends TestSuite {
   }
 
   TestCase _makeNormalTestCase(name, expectations) {
-    var command = new Command(Platform.executable,
+    var command = new Command('custom',
+                              Platform.executable,
                               [Platform.script, name]);
     return _makeTestCase(name, DEFAULT_TIMEOUT, command, expectations);
   }
 
   _makeCrashTestCase(name, expectations) {
-    var crashCommand = new Command(getProcessTestFileName(),
+    var crashCommand = new Command('custom_crash',
+                                   getProcessTestFileName(),
                                    ["0", "0", "1", "1"]);
     // The crash test sometimes times out. Run it with a large timeout
     // to help diagnose the delay.