patch 8.2.2417: condition stack values may be used when not set

Problem:    Condition stack values may be used when not set.
Solution:   Clear cs_script_var_len and cs_block_id just in case they get used
            later. (issue #7733)
diff --git a/src/ex_eval.c b/src/ex_eval.c
index 94338fc..ad9de26 100644
--- a/src/ex_eval.c
+++ b/src/ex_eval.c
@@ -920,6 +920,13 @@
 	cstack->cs_block_id[cstack->cs_idx] = ++si->sn_last_block_id;
 	si->sn_current_block_id = si->sn_last_block_id;
     }
+    else
+    {
+	// Just in case in_vim9script() does not return the same value when the
+	// block ends.
+	cstack->cs_script_var_len[cstack->cs_idx] = 0;
+	cstack->cs_block_id[cstack->cs_idx] = 0;
+    }
 }
 
     static void