Add issue numbers to language tests status files

tests/language/null_hashcode_optimized_vm_test.dart

Index: tests/language/null_hashcode_optimized_vm_test.dart
diff --git a/tests/language/null_hashcode_optimized_vm_test.dart b/tests/language/null_hashcode_optimized_vm_test.dart
deleted file mode 100644
index a214c2916511270ddc057fc2f464479e1540d624..0000000000000000000000000000000000000000
--- a/tests/language/null_hashcode_optimized_vm_test.dart
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright (c) 2013, 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.
-// Test that optimized Object.hashCode works for the null receiver.
-// VMOptions=--optimization_counter_threshold=10
-
-main() {
-  for (int i = 0; i < 20; i++) {
-    foo(null);
-  }
-}
-
-foo(a) => a.hashCode;