vim-patch:8.2.3795: too many #ifdefs

Problem:    Too many #ifdefs.
Solution:   Graduate the jumplist feature.

https://github.com/vim/vim/commit/739f13a55b4982efb37ebc9282e7f79975fff982

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/undo.c

@@ -250,7 +250,7 @@ int u_save_cursor(void)
 }
 
 /// Save the lines between "top" and "bot" for both the "u" and "U" command.
-/// "top" may be 0 and bot may be curbuf->b_ml.ml_line_count + 1.
+/// "top" may be 0 and "bot" may be curbuf->b_ml.ml_line_count + 1.
 /// Careful: may trigger autocommands that reload the buffer.
 /// Returns FAIL when lines could not be saved, OK otherwise.
 int u_save(linenr_T top, linenr_T bot)

test/old/testdir/test_jumplist.vim

@@ -2,10 +2,6 @@
 
 " Tests for the getjumplist() function
 func Test_getjumplist()
-  if !has("jumplist")
-    return
-  endif
-
   %bwipe
   clearjumps
   call assert_equal([[], 0], getjumplist())