REGTESTS: connection: test the NetScaler CIP protocol

REGTESTS: connection: test the NetScaler CIP protocol

Neither the "accept-netscaler-cip" bind keyword nor the
"tcp-request connection expect-netscaler-cip layer4" action had any
coverage, the notes listing them as doable now that the expect-proxy
test shows the pattern, the only obstacle being that the CIP header has
to be built by hand. It is built with sendhex here, in its standard
form, and the test follows the structure of the expect-proxy one.

The first frontend declares the magic number on its bind line, which
makes the header mandatory: a well-formed IPv4 header, then an IPv6 one,
replace the addresses of the session while fc_src keeps reporting the
real peer, whereas a wrong magic, an encapsulated protocol which is not
TCP, and a request with no header at all are all rejected.

The second frontend uses the action, which only expects the header from
the sources matching its condition. Note that the action reads the
magic number from the bind line, so without "accept-netscaler-cip"
there the expected magic is zero, which the test documents.