selftests/bpf: Move reuseport tests under prog_tests/

Do a pure move the show the actual work needed to adapt the tests in
subsequent patch at the cost of breaking test_progs build for the moment.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20191212102259.418536-10-jakub@cloudflare.com

tools/testing/selftests/bpf/Makefile

@@ -28,7 +28,7 @@ LDLIBS += -lcap -lelf -lrt -lpthread
 TEST_GEN_PROGS = test_verifier test_tag test_maps test_lru_map test_lpm_map test_progs \
 	test_align test_verifier_log test_dev_cgroup test_tcpbpf_user \
 	test_sock test_btf test_sockmap get_cgroup_id_user test_socket_cookie \
-	test_cgroup_storage test_select_reuseport \
+	test_cgroup_storage \
 	test_netcnt test_tcpnotify_user test_sock_fields test_sysctl test_hashmap \
 	test_cgroup_attach test_progs-no_alu32