Instead of creating an X11 connection to test that X11 is available,
closing the connection, and then reconnecting for real, use the same
connection to handle both cases.
The X11 connection retry delay mechanism in the case where X11 is
dynamically loaded has been removed. It was only necessary to avoid
authetnication token reuse from the XOpenDisplay call that used to
exist in X11_Available. Now that this call is only made once, it
is no longer needed.
Also drop unused and inapplicable code from a comment.
***
The two are only ever called together, and combining them makes it possible
to eliminate redundant symbol loading and redundant attempts to connect
to a display server.