vim-patch:8.2.0195: some tests fail when run in the GUI

Problem:    Some tests fail when run in the GUI.
Solution:   Make sure the window width is enough.  In the GUI run terminal Vim
            in the terminal, if possible.

3180fe6c6d

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

test/old/testdir/test_highlight.vim

@@ -595,6 +595,8 @@ endfunc
 
 func Test_wincolor()
   CheckScreendump
+  " make sure the width is enough for the test
+  set columns=80
 
   let lines =<< trim END
 	set cursorline cursorcolumn rnu