Fix static warnings in generic_instanceof4_test.

tests/language/generic_instanceof4_test.dart

Index: tests/language/generic_instanceof4_test.dart
diff --git a/tests/language/generic_instanceof4_test.dart b/tests/language/generic_instanceof4_test.dart
index 447e0abe42308c9f93b5b3d8f44cda8e02e803e2..15896cb598551432d7733e177b4fbde3ecb3387b 100644
--- a/tests/language/generic_instanceof4_test.dart
+++ b/tests/language/generic_instanceof4_test.dart
@@ -18,7 +18,7 @@ class BB {}
 class B<T> implements BB {
   foo() {
     // Don't inline.
-    if (new DateTime.now().millisecondsSinceEpoch == 42) return foo(x);
+    if (new DateTime.now().millisecondsSinceEpoch == 42) return foo();
     return new A<T>().foo(new B());
   }
 }