patch 9.1.0805: tests: minor issues in gen_opt_test.vim

Problem:  tests: minor issues in gen_opt_test.vim
Solution: fix restore value for 'undolevels', fix comment, fix
          wrong cpo value, add equality test for global-local options on
          switchback (Milly).

closes: #15913

Signed-off-by: Milly <milly.ca@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/version.c b/src/version.c
index 59260d1..8f1d606 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    805,
+/**/
     804,
 /**/
     803,