patch 8.1.0016: possible crash in term_wait()

Problem:    Possible crash in term_wait(). (Dominique Pelle)
Solution:   Check for a valid buffer after ui_delay(). (closes #2944)

Author: brammool

src/terminal.c

@@ -5264,11 +5264,11 @@ f_term_wait(typval_T *argvars, typval_T *rettv UNUSED)
 	{
 	    mch_check_messages();
 	    parse_queued_messages();
+	    ui_delay(10L, FALSE);
 	    if (!buf_valid(buf))
 		/* If the terminal is closed when the channel is closed the
 		 * buffer disappears. */
 		break;
-	    ui_delay(10L, FALSE);
 	}
 	mch_check_messages();
 	parse_queued_messages();

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    16,
 /**/
     15,
 /**/