patch 8.2.2611: conditions for startup tests are not exactly right

Problem:    Conditions for startup tests are not exactly right.
Solution:   Check for type of GUI instead of MS-Windows. (Ozaki Kiichi,
            closes #7976)

src/testdir/check.vim

@@ -199,4 +199,29 @@ func CheckNotAsan()
   endif
 endfunc
 
+" Command to check for satisfying any of the conditions.
+" e.g. CheckAnyOf Feature:bsd Feature:sun Linux
+command -nargs=+ CheckAnyOf call CheckAnyOf(<f-args>)
+func CheckAnyOf(...)
+  let excp = []
+  for arg in a:000
+    try
+      exe 'Check' .. substitute(arg, ':', ' ', '')
+      return
+    catch /^Skipped:/
+      let excp += [substitute(v:exception, '^Skipped:\s*', '', '')]
+    endtry
+  endfor
+  throw 'Skipped: ' .. join(excp, '; ')
+endfunc
+
+" Command to check for satisfying all of the conditions.
+" e.g. CheckAllOf Unix Gui Option:ballooneval
+command -nargs=+ CheckAllOf call CheckAllOf(<f-args>)
+func CheckAllOf(...)
+  for arg in a:000
+    exe 'Check' .. substitute(arg, ':', ' ', '')
+  endfor
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab