This change ensures consistency and compatibility for both GNU Emacs
and XEmacs because:

* XEmacs doesn't support -Q and ignores it; and
* the different releases of GNU Emacs handle it differently, or not at
   all.

With GNU Emacs, '-Q' was added in 22.1, and specifying it on earlier
versions causes an immediate abort.  Also, the meaning of '-Q' changes
in 24.1 where it also implies/uses a new '--no-site-lisp' option.
This new option means it won't add the site-lisp directories to
`load-path', but they need to be there because `am_cv_lispdir' is
looking for them.

Tested on GNU Emacs 21.4, 24.3, 27.2, 28.2, and XEmacs 21.5.

 From this testing I think the existing usage of '--no-site-file'
is good to stay as it's the one mentioned in the current GNU Emacs
manual and recognized back to at least 19.34.  Also, whilst the
XEmacs manual and '--help' mention "-no-site-file" it also
supports "--no-site-file".