patch 8.2.4632: using freed memory in flatten()

Problem:    Using freed memory in flatten().
Solution:   Clear typval after recursing into list.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4632,
 /**/
     4631,
 /**/