patch 8.2.4236: accessing freed memory

Problem:    Accessing freed memory.
Solution:   Set the bh_curr pointer to NULL.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4236,
 /**/
     4235,
 /**/