bpf: selftests: Support custom type and proto for client sockets

Extend connect_to_fd_opts() to take optional type and protocol
parameters for the client socket. These parameters are useful when
opening a raw socket to send IP fragments.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/r/9067db539efdfd608aa86a2b143c521337c111fc.1689970773.git.dxu@dxuuu.xyz


Signed-off-by: Alexei Starovoitov <ast@kernel.org>