This abolishes the test.sh script which spawns a bunch of `openssl` instances to
instead run/manage the binary in-process (providing more isolation to boot). The
tests have been updated accordingly and the `connected_socket` dependency was
also dropped in favor of `net2` as it the former doesn't work on Windows.
Heavily based on the existing NPN wrapping code. Naming of public
functions is identical to the NPN ones with `s/npn/alpn/` applied to
prevent devs from needing to remember 2 names (and to let my copy the
npn tests and perform the subistution to generate the apln tests).
It might make sense to (at some point) use macros or a trait to cut down
the duplication.
Steven Fackler