patch 9.0.1320: checking the type of a null object causes a crash

Problem:    Checking the type of a null object causes a crash.
Solution:   Don't try to get the class of a null object. (closes #12005)
            Handle error from calling a user function better.

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1320,
 /**/
     1319,
 /**/