Tighten up handling of new classes

1b1d133b added the process2 class but
forgot to suppress SELinux denials associated with these permissions
for the su domain. Suppress them.

Ensure xdp_socket is in socket_class_set, so the existing dontaudit rule
in su.te is relevant. Inspired by
https://github.com/SELinuxProject/refpolicy/commit/66a337eec6d7244e44e51936835b4e904f275a02

Add xdp_socket to various other neverallow rules.

Test: policy compiles.
Change-Id: If5422ecfa0cc864a51dd69559a51d759e078c8e7