Revert "highlight: skip processing the same hi group twice"

This reverts commit feee9bcf3c.

It brakes CI and shouldn't be needed

autoload/airline.vim

@@ -47,9 +47,7 @@ function! airline#load_theme()
   endif
 
   call airline#highlighter#load_theme()
-  let g:airline_theme_dict = {}
   call airline#extensions#load_theme()
-  unlet g:airline_theme_dict
   call airline#update_statusline()
 endfunction
 
@@ -104,7 +102,6 @@ function! airline#update_statusline()
   if airline#util#getwinvar(winnr(), 'airline_disabled', 0)
     return
   endif
-  let g:airline_theme_dict={}
   for nr in filter(range(1, winnr('$')), 'v:val != winnr()')
     if airline#util#getwinvar(nr, 'airline_disabled', 0)
       continue
@@ -120,7 +117,6 @@ function! airline#update_statusline()
   let w:airline_active = 1
   let context = { 'winnr': winnr(), 'active': 1, 'bufnr': winbufnr(winnr()) }
   call s:invoke_funcrefs(context, g:airline_statusline_funcrefs)
-  unlet g:airline_theme_dict
 endfunction
 
 let s:contexts = {}
@@ -202,11 +198,9 @@ function! airline#check_mode(winnr)
     return ''
   endif
   if get(w:, 'airline_lastmode', '') != mode_string
-    let g:airline_theme_dict = {}
     call airline#highlighter#highlight_modified_inactive(context.bufnr)
     call airline#highlighter#highlight(l:mode, context.bufnr)
     let w:airline_lastmode = mode_string
-    unlet g:airline_theme_dict
   endif
 
   return ''

autoload/airline/extensions/tabline.vim

@@ -118,8 +118,6 @@ function! airline#extensions#tabline#get()
   if !exists('#airline#BufAdd#*')
     autocmd airline BufAdd * call <sid>update_tabline()
   endif
-  try
-    let g:airline_theme_dict = {}
   if s:ctrlspace
     return airline#extensions#tabline#ctrlspace#get()
   elseif s:show_buffers && curtabcnt == 1 || !s:show_tabs
@@ -127,9 +125,6 @@ function! airline#extensions#tabline#get()
   else
     return airline#extensions#tabline#tabs#get()
   endif
-  finally
-    unlet g:airline_theme_dict
-  endtry
 endfunction
 
 function! airline#extensions#tabline#title(n)

autoload/airline/highlighter.vim

@@ -84,10 +84,6 @@ function! airline#highlighter#exec(group, colors)
   if len(colors) == 4
     call add(colors, '')
   endif
-  if has_key(g:airline_theme_dict, 'a:group') &&
-        \ get(g:airline_theme_dict[a:group]) == a:colors
-    return
-  endif
   if g:airline_gui_mode ==# 'gui'
     let new_hi = [colors[0], colors[1], '', '', colors[4]]
   else
@@ -102,7 +98,6 @@ function! airline#highlighter#exec(group, colors)
         \ s:Get(colors, 4, 'term=', ''))
     exe cmd
   endif
-  let g:airline_theme_dict[a:group] = a:colors
 endfunction
 
 function! s:CheckDefined(colors)
@@ -165,7 +160,6 @@ function! airline#highlighter#load_theme()
   if pumvisible()
     return
   endif
-  let g:airline_theme_dict = {}
   for winnr in filter(range(1, winnr('$')), 'v:val != winnr()')
     call airline#highlighter#highlight_modified_inactive(winbufnr(winnr))
   endfor
@@ -175,7 +169,6 @@ function! airline#highlighter#load_theme()
   else
     call airline#highlighter#highlight(['normal'])
   endif
-  unlet g:airline_theme_dict
 endfunction
 
 function! airline#highlighter#add_separator(from, to, inverse)