dns/dnsmessage: remove unused funcs skipText and skipBytes
dns/dnsmessage: remove unused funcs skipText and skipBytes

Change-Id: Ie34e3ec7e83ac98181725238e0010ddb941174c7
Reviewed-on: https://go-review.googlesource.com/c/net/+/220457
Run-TryBot: Tobias Klauser <0a68dd4915066ec5d3f81f75a828fee53dcc8822@gmail.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Matt Layher <76528ff2e917253aa2211f68e4ca60b5b846dcf5@gmail.com>

golang/net