Also now permit interactivly running tests without explicitly setting
$srcdir. This now works if we are inside ./tests and fails, as before,
when we are in a different directory.
Detected by shellcheck via CodeFactor.io
Add SNI hostname if and only if host is not a bare IP address
Rename sndrcv_tls_anon -> sndrcv_tls_anon_hostname, and include a hostname in this test
Add bare IPv4 and IPv6 TLS tests
Change port in some tests to make wireshark traces easier to interpret during a full test run