build: remove --xcode configure switch

`./configure --xcode` ostensibly let you built with the Xcode IDE but
it has never been tested regularly since its introduction in 2012 and
probably has been broken for years.  Remove it.

PR-URL: https://github.com/nodejs/node/pull/20328
Fixes: https://github.com/nodejs/node/issues/20324


Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Beth Griggs <Bethany.Griggs@uk.ibm.com>
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>