UBUNTU: SAUCE: selftests: net: tls: remove recv_rcvbuf test

UBUNTU: SAUCE: selftests: net: tls: remove recv_rcvbuf test

This test only works when [1] is applied, which was rejected.

Basically, the errors are reported and cleared. In this particular case of tls
sockets, following reads will block.

The test case was originally submitted with the rejected patch, but, then, was
included as part of a different patchset, possibly by mistake.

[1] https://lore.kernel.org/netdev/20191007035323.4360-2-jakub.kicinski@netronome.com/#t

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Acked-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Acked-by: Paolo Pisati <paolo.pisati@canonical.com>
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>