patch 9.0.1557: test failures for unreachable code

Problem:    Test failures for unreachable code.
Solution:   Add a test override to ignore unreachable code.
diff --git a/src/vim9cmds.c b/src/vim9cmds.c
index bc01cd8..c3c900a 100644
--- a/src/vim9cmds.c
+++ b/src/vim9cmds.c
@@ -1578,7 +1578,8 @@
 	return NULL;
     }
 
-    if (scope->se_u.se_try.ts_caught_all)
+    if (scope->se_u.se_try.ts_caught_all
+				       && !ignore_unreachable_code_for_testing)
     {
 	emsg(_(e_catch_unreachable_after_catch_all));
 	return NULL;