With https://github.com/libp2p/rust-libp2p/pull/3454 merged we can now test the
new rust-libp2p QUIC implementation based on upstream quinn directly from
rust-libp2p `master`.
This commit does the following in libp2p/test-plans:
1. Remove the `perf/impl/rust-libp2p-quinn` implementation.
2. Introduce the `perf/impl/rust-libp2p/master` version of the rust-libp2p implementation.
We can promote the latter to a proper version on the next rust-libp2p release.
