skip test::sys::test_af_alg_cipher on s390x/Linux too

[decathorpe]

It appears that s390x-unknown-linux-gnu is also affected by issue #1352:

---- sys::test_socket::test_af_alg_cipher stdout ----
thread 'sys::test_socket::test_af_alg_cipher' (1118) panicked at test/sys/test_socket.rs:961:39:
bind failed: ENOENT

This PR just adds the s390x/Linux configuration to the list of environments where this specific test is skipped.