patch 9.0.1321: vimscript test fails where using {expr} syntax

Problem:    vimscript test fails where using {expr} syntax.
Solution:   Only return FCERR_FAILED in call_user_func() for Vim9 script.

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1321,
 /**/
     1320,
 /**/