Don't create GUI frames in batch sessions

Don't create GUI frames in batch sessions

This resolves an issue with running test/lisp/server-tests.el when
'DISPLAY' is set: the tests would start the Emacs server in a batch
session, and then request a new GUI frame.  However, that caused the
tests to terminate with SIGIO, since a batch Emacs doesn't set a SIGIO
handler.

Ref: <https://lists.gnu.org/archive/html/emacs-devel/2023-02/msg00879.html>

* lisp/frame.el (make-frame): Always create a terminal frame in batch
sessions.