libp2p(@webrtc): Add transport compliance tests

[achingbrain]

Now that this transport can listen for incoming connections (e.g. browser to browser), it should be able run the interface transport compliance test suite.

This will ensure it implements the interface in a way consistent with other transports.

[maschad]

Are you planning on taking this on @achingbrain ? If not I'd be happy to.

[p-shahi]

Blocked on #1852