Move LockdownVpnTrackerTest to FrameworksVpnNets

LockdownVpnTrackerTest was put inside FrameworksServiceTest
because there is no better place to put the test. This VPN
related test should be better to be placed together with
other VPN related tests.

Also update the TEST_MAPPING to run the test accurately.

Test: atest FrameworksVpnTests
Change-Id: I2d90e401e3d0a6eea4a047a0079b28bba7aa15ed
2 files changed