patch 9.0.1353: too many "else if" statements to handle option values

Problem:    Too many "else if" statements to handle option values.
Solution:   Add more functions to handle option value changes. (Yegappan
            Lakshmanan, closes #12058)
diff --git a/src/testdir/gen_opt_test.vim b/src/testdir/gen_opt_test.vim
index a18aa66..6124bb2 100644
--- a/src/testdir/gen_opt_test.vim
+++ b/src/testdir/gen_opt_test.vim
@@ -104,6 +104,7 @@
       \ 'guifont': [['', fontname], []],
       \ 'guifontwide': [['', fontname], []],
       \ 'guifontset': [['', fontname], []],
+      \ 'guioptions': [['', 'a'], ['Q']],
       \ 'helplang': [['', 'de', 'de,it'], ['xxx']],
       \ 'highlight': [['', 'e:Error'], ['xxx']],
       \ 'imactivatekey': [['', 'S-space'], ['xxx']],