patch 8.1.1012: memory leak with E461

Problem:    Memory leak with E461.
Solution:   Clear the typeval. (Dominique Pelle, closes #4111)
diff --git a/src/eval.c b/src/eval.c
index 9e1ac6d..82be5c0 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -2138,6 +2138,7 @@
 			 || &lp->ll_dict->dv_hashtab == get_funccal_args_ht())
 		{
 		    semsg(_(e_illvar), name);
+		    clear_tv(&var1);
 		    return NULL;
 		}