Remove ARI check for multiple calls to warning or error

Remove ARI check for multiple calls to warning or error

ARI has a check for multiple calls to warning or error, suggesting
that they be combined into a single call.  This triggers at three
places in gdb -- throw_bad_regnum_error, guile_repl_command, and the
end of value_cast -- and after examining these, I think they all make
sense as-is.  Instead, it makes sense to remove this check from ARI.

gdb/ChangeLog
2019-12-13  Tom Tromey  <tromey@adacore.com>

	* contrib/ari/gdb_ari.sh: Remove check for multiple calls to
	warning or error.

Change-Id: I0618683623a3c7324460c7b9e5d7f252d88c2e8d