Gardening: mark language/regress_28255_test SkipByDesign in configurations without mirrors.

R=kustermann@google.com
BUG=

Review-Url: https://codereview.chromium.org/2610163005 .
diff --git a/tests/language/language.status b/tests/language/language.status
index 7751d68..8697ac4 100644
--- a/tests/language/language.status
+++ b/tests/language/language.status
@@ -205,6 +205,7 @@
 super_call4_test: SkipByDesign
 super_getter_setter_test: SkipByDesign
 vm/reflect_core_vm_test: SkipByDesign
+regress_28255_test: SkipByDesign
 
 [ $noopt ]
 # Deferred loading happens eagerly. Issue #27587