patch 8.2.2415: no way to check for the cmdwin feature

Problem:    No way to check for the cmdwin feature, cmdline_hist is now always
            enabled.
Solution:   Add has('cmdwin') support. Skip arglist test on Windows
            temporarily.
diff --git a/src/testdir/test_autocmd.vim b/src/testdir/test_autocmd.vim
index 5ec854e..60369c2 100644
--- a/src/testdir/test_autocmd.vim
+++ b/src/testdir/test_autocmd.vim
@@ -2397,10 +2397,8 @@
 
 func Test_autocmd_CmdWinEnter()
   CheckRunVimInTerminal
-  " There is not cmdwin switch, so
-  " test for cmdline_hist
-  " (both are available with small builds)
-  CheckFeature cmdline_hist
+  CheckFeature cmdwin
+
   let lines =<< trim END
     let b:dummy_var = 'This is a dummy'
     autocmd CmdWinEnter * quit