Add test for cgroup bpf program status

This is useful to ensure cgroup bpf program is attached,
which would lead to hard-debugging uid stats missing problem.

Test: atest ConnectivityServiceIntegrationTest#testBpfProgramAttachStatus
Bug: 292156770
Change-Id: I16370497484aff29ed41cbb0d160e530731e1a4e
2 files changed