[bgpvpn] Bring in L2/L3 VPN endpoints tests

Closes-Bug: PRODX-11809
Closes-Bug: PRODX-11810
Change-Id: Iac179b592e579916fc36bef79b1a007528a07f36
(cherry picked from commit 35829e1bec9aa92a3cf90d371892dc900d6364ad)
(cherry picked from commit 7227eec12b83854694c22b7eb7ae37379931f5c0)
(cherry picked from commit 3e5d783f9d34cb9cc093a3dd451ec8aa559cb597)
(cherry picked from commit ef22edabe140965c19dcee18d7b10f98ede28326)
2 files changed