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_findfile.vim b/src/testdir/test_findfile.vim
new file mode 100644
index 0000000..85e5cd2
--- /dev/null
+++ b/src/testdir/test_findfile.vim
@@ -0,0 +1,25 @@
+" Test for findfile()
+"
+func Test_findfile()
+  new
+  let cwd=getcwd()
+  cd ..
+
+  " Tests may be run from a shadow directory, so an extra cd needs to be done to
+  " get above src/
+  if fnamemodify(getcwd(), ':t') != 'src'
+    cd ../.. 
+  else 
+    cd .. 
+  endif
+  set ssl
+
+  call assert_equal('src/testdir/test_findfile.vim', findfile('test_findfile.vim','src/test*'))
+  exe "cd" cwd
+  cd ..
+  call assert_equal('testdir/test_findfile.vim', findfile('test_findfile.vim','test*'))
+  call assert_equal('testdir/test_findfile.vim', findfile('test_findfile.vim','testdir'))
+
+  exe "cd" cwd
+  q!
+endfunc