Ensure libraries always have at least one top-level class and therefore at least one script.

tests/lib/lib.status

Index: tests/lib/lib.status
diff --git a/tests/lib/lib.status b/tests/lib/lib.status
index b6dfec5e158809eebaa139de8be3b15ffe67f33d..c63057924b96ea085f311ff9969c9b591f1dd9e4 100644
--- a/tests/lib/lib.status
+++ b/tests/lib/lib.status
@@ -19,6 +19,7 @@ mirrors/closurization_equivalence_test: RuntimeError # Issue 6490
 mirrors/constructor_kinds_test: RuntimeError # Issue 13799
 mirrors/constructor_private_name_test: CompileTimeError # Issue 13597
 mirrors/deferred_type_test: RuntimeError # Issue 6335
+mirrors/empty_test: RuntimeError # Issue 6490
 mirrors/enum_test: RuntimeError # Issue 6490
 mirrors/fake_function_with_call_test: RuntimeError # Issue 11612
 mirrors/fake_function_without_call_test: RuntimeError # Issue 11612
@@ -231,7 +232,6 @@ mirrors/deferred_type_test: CompileTimeError, OK # Don't have a multitest marker
 async/timer_not_available_test: SkipByDesign # only meant to test when there is no way to implement timer (currently only in d8)
 
 mirrors/symbol_validation_test: RuntimeError # Issue 13596
-mirrors/mirrors_reader_test: Crash #Issue 23483
 
 mirrors/mirrors_used*: SkipByDesign # Invalid tests. MirrorsUsed does not have a specification, and dart:mirrors is not required to hide declarations that are not covered by any MirrorsUsed annotation.