patch 8.0.0359: 'number' and 'relativenumber' are not properly tested

Problem:    'number' and 'relativenumber' are not properly tested.
Solution:   Add tests, change old style to new style tests. (Ozaki Kiichi,
            closes #1447)
diff --git a/src/testdir/test_alot.vim b/src/testdir/test_alot.vim
index ef0edc7..699e093 100644
--- a/src/testdir/test_alot.vim
+++ b/src/testdir/test_alot.vim
@@ -16,6 +16,7 @@
 source test_fileformat.vim
 source test_filter_cmd.vim
 source test_filter_map.vim
+source test_findfile.vim
 source test_float_func.vim
 source test_fnamemodify.vim
 source test_functions.vim