vim-patch:8.1.0811: too many #ifdefs

Problem:    Too many #ifdefs.
Solution:   Graduate FEAT_MBYTE, the final chapter.
30276f2beb

src/nvim/testdir/test_visual.vim

@@ -2,9 +2,6 @@
 
 func Test_block_shift_multibyte()
   " Uses double-wide character.
-  if !has('multi_byte')
-    return
-  endif
   split
   call setline(1, ['xヹxxx', 'ヹxxx'])
   exe "normal 1G0l\<C-V>jl>"