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.
diff --git a/src/testdir/test_highlight.vim b/src/testdir/test_highlight.vim
index f718e90..ac6a101 100644
--- a/src/testdir/test_highlight.vim
+++ b/src/testdir/test_highlight.vim
@@ -594,6 +594,8 @@
 
 func Test_wincolor()
   CheckScreendump
+  " make sure the width is enough for the test
+  set columns=80
 
   let lines =<< trim END
 	set cursorline cursorcolumn rnu
@@ -686,7 +688,8 @@
   endif
 endfunc
 
-function Test_no_space_before_xxx()
+" Do this test last, sometimes restoring the columns doesn't work
+function Test_z_no_space_before_xxx()
   let l:org_columns = &columns
   set columns=17
   let l:hi_StatusLineTermNC = join(split(execute('hi StatusLineTermNC')))