patch 8.1.0038: popup test causes Vim to exit

Problem:    Popup test causes Vim to exit.
Solution:   Disable the broken part of the test for now.

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    38,
 /**/
     37,
 /**/