tests: add 2n1l l2 acl tests, update 2n-tx2 specs

Modify initialize L2BD ACL keywords to be usable for both 2-node and
3-node topologies and update testsuites accordingly.
Add the missing macip T-rex profile.
Add classifier tests to 2n-tx2 job specs.

Change-Id: I17b84b8fc18ef9a6f275ae0238a0665ac2017f01
Signed-off-by: Juraj Linkeš <juraj.linkes@pantheon.tech>