patch 8.2.2908: crash when using a terminal popup window from cmdline window

Problem:    Crash when using a terminal popup window from the cmdline window.
Solution:   Instead of checking cmdwin_type call cmdwin_is_active().
            (closes #8286)
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index c3a638b..8b7015b 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -1192,6 +1192,20 @@
   call delete('XTest_restore')
 endfunc
 
+func Test_cmdwin_no_terminal()
+  CheckFeature cmdwin
+  CheckFeature terminal
+
+  let buf = RunVimInTerminal('', {'rows': 12})
+  call TermWait(buf, 50)
+  call term_sendkeys(buf, ":set cmdheight=2\<CR>")
+  call term_sendkeys(buf, "q:")
+  call term_sendkeys(buf, ":let buf = term_start(['/bin/echo'], #{hidden: 1})\<CR>")
+  call VerifyScreenDump(buf, 'Test_cmdwin_no_terminal', {})
+  call term_sendkeys(buf, ":q\<CR>")
+  call StopVimInTerminal(buf)
+endfunc
+
 func Test_buffers_lastused()
   " check that buffers are sorted by time when wildmode has lastused
   call test_settime(1550020000)	  " middle