Revert "Make VPN more testable and update NC during network change"

Revert submission 2113906-mobike-ut

Reason for revert: b/235853154 Test files build failed on tm-mainline-prod
Reverted Changes:
I739016db1:Add unit tests for IKEv2 VPN setup and MOBIKE
Ic0f0c5496:Make VPN more testable and update NC during networ...

Change-Id: Ia598f1c0feb74ead57e3ce32413cc7da9dab73e5