Proposals pile up: SSH transport callback, goanalysis experiment, power9 floor

Three proposals land together and pull in different directions: x/crypto/ssh gains a TransportReadyCallback hook on ClientConfig for code that needs to act between the transport and auth layers, a GOEXPERIMENT=goanalysis flag is floated to guard the in-progress analyzer support for go test, and there is a pitch to lift the minimum GOPPC64 to power9 at least two release cycles out. Over on the lists, Boris Schaa picks at testing.T.Context and how it changes the Context habits everyone built up before 1.24, which is the quieter but more immediately useful read if you write tests for a living.