crypto/tls: use context.AfterFunc in handshakeContext
This saves a goroutine when ctx can be canceled but is not canceled
during the handshakeContext call.
Use ctx consistently, because in this path (c.quic == nil) handshakeCtx
will only be canceled when ctx is canceled.
Change-Id: I7f4565119f30d589dce026b0d7ef3c324220525a
Reviewed-on: https://go-review.googlesource.com/c/go/+/699895 Reviewed-by: Roland Shoemaker <roland@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Daniel McCarney <daniel@binaryparadox.net> Reviewed-by: Michael Pratt <mpratt@google.com>