Workaround: Omit 'fullscreen' option test

Doing 'set fullscreen' and 'set nofullscreen' at once doesn't work
properly: the values of "&lines" and "&columns" are restored, but the
fullscreen is kept on actually and thus affects 'writedelay' test
performance.

Author: ichizok

src/testdir/gen_opt_test.vim

@@ -188,10 +188,12 @@ while 1
   endif
   if len(a[0]) > 0 || len(a[1]) > 0
     if line =~ 'P_BOOL'
-      call add(script, 'set ' . name)
-      call add(script, 'set ' . shortname)
-      call add(script, 'set no' . name)
-      call add(script, 'set no' . shortname)
+      if name != 'fullscreen'
+        call add(script, 'set ' . name)
+        call add(script, 'set ' . shortname)
+        call add(script, 'set no' . name)
+        call add(script, 'set no' . shortname)
+      endif
     else
       for val in a[0]
 	call add(script, 'set ' . name . '=' . val)