patch 8.1.2317: no test for spell affix file with flag on suffix

Problem:    No test for spell affix file with flag on suffix.
Solution:   Add a test case.
diff --git a/src/version.c b/src/version.c
index aae3fae..42100a0 100644
--- a/src/version.c
+++ b/src/version.c
@@ -742,6 +742,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2317,
+/**/
     2316,
 /**/
     2315,