patch 8.1.0116: display problem with 'vartabstop' and 'linebreak'

Problem:    Display problem with 'vartabstop' and 'linebreak'. (Chauca
            Fuentes)
Solution:   Call tabstop_padding(). (Christian Brabandt, closes #3076)

src/screen.c

@@ -4753,8 +4753,13 @@ win_line(
		    n_extra = win_lbr_chartabsize(wp, line, p, (colnr_T)vcol,
								    NULL) - 1;
		    if (c == TAB && n_extra + col > wp->w_width)
#ifdef FEAT_VARTABS
			n_extra = tabstop_padding(vcol, wp->w_buffer->b_p_ts,
					wp->w_buffer->b_p_vts_array) - 1;
#else
			n_extra = (int)wp->w_buffer->b_p_ts
				       - vcol % (int)wp->w_buffer->b_p_ts - 1;
 #endif

# ifdef FEAT_MBYTE
		    c_extra = mb_off > 0 ? MB_FILLER_CHAR : ' ';

src/testdir/test_vartabs.vim

@@ -4,6 +4,11 @@ if !has("vartabs")
  finish
endif

source view_util.vim
function! s:compare_lines(expect, actual)
  call assert_equal(join(a:expect, "\n"), join(a:actual, "\n"))
endfunction

func! Test_vartabs()
  new
  %d
@@ -255,3 +260,23 @@ func! Test_vartabs_breakindent()

  bwipeout!
endfunc

func! Test_vartabs_linebreak()
  if winwidth(0) < 80
    return
  endif
  new
  70vnew
  %d
  setl linebreak vartabstop=10,15,20,40
  call setline(1, "\tx\tx\tx\tx")

  let lines = ScreenLines([1, 2], winwidth(0))
  let expect = ['          x              x                   x                        ',
        \       '               x                                                      ']
  call s:compare_lines(expect, lines)

  " cleanup
  bw!
  bw!
endfunc

src/version.c

@@ -789,6 +789,8 @@ static char *(features[]) =

static int included_patches[] =
{   /* Add new patch number below this line */
/**/
    116,
/**/
    115,
/**/