vim-patch:8.1.2340: quickfix test fails under valgrind and asan

Problem:    Quickfix test fails under valgrind and asan.
Solution:   Make sure long line does not overflow IObuff. (Dominique Pelle,
            closes vim/vim#5263)  Put back fix for large terminals. (Yegappan
            Lakshmanan, closes vim/vim#5264)
a106e6cde6

src/nvim/testdir/test_quickfix.vim

@@ -554,6 +554,33 @@ func s:test_xhelpgrep(cchar)
   " This wipes out the buffer, make sure that doesn't cause trouble.
   Xclose
 
+  " When the current window is vertically split, jumping to a help match
+  " should open the help window at the top.
+  only | enew
+  let w1 = win_getid()
+  vert new
+  let w2 = win_getid()
+  Xnext
+  let w3 = win_getid()
+  call assert_true(&buftype == 'help')
+  call assert_true(winnr() == 1)
+  " See jump_to_help_window() for details
+  let w2_width = winwidth(w2)
+  if w2_width != &columns && w2_width < 80
+    call assert_equal(['col', [['leaf', w3],
+          \ ['row', [['leaf', w2], ['leaf', w1]]]]], winlayout())
+  else
+    call assert_equal(['row', [['col', [['leaf', w3], ['leaf', w2]]],
+          \ ['leaf', w1]]] , winlayout())
+  endif
+
+  new | only
+  set buftype=help
+  set modified
+  call assert_fails('Xnext', 'E37:')
+  set nomodified
+  new | only
+
   if a:cchar == 'l'
       " When a help window is present, running :lhelpgrep should reuse the
       " help window and not the current window