patch 9.0.1866: undo is synced after character find

Problem:  Undo is synced after character find.
Solution: Set no_u_sync when calling gotchars_nop().

closes: #13022
closes: #13024

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>

src/testdir/test_undo.vim

@@ -862,5 +862,15 @@ func Test_undo_after_write()
   call delete('Xtestfile.txt')
 endfunc
 
+func Test_undo_range_normal()
+  new
+  call setline(1, ['asa', 'bsb'])
+  let &l:undolevels = &l:undolevels
+  %normal dfs
+  call assert_equal(['a', 'b'], getline(1, '$'))
+  undo
+  call assert_equal(['asa', 'bsb'], getline(1, '$'))
+  bwipe!
+endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab