patch 8.2.1282: Vim9: crash when using CheckScriptFailure()

Problem:    Vim9: crash when using CheckScriptFailure() in
            Test_vim9script_call_fail_decl().
Solution:   Do not decrement the def_functions len unless the function was
            newly added.

src/version.c

@@ -754,6 +754,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1282,
 /**/
     1281,
 /**/