Move ConnectivityCoverageTests to mainline-presubmit

Recent runs have been passing in mainline-postsubmit.

Non-mainline presubmit will be added later, after it has been passing
consistently for some time.

Bug: 187935317
Change-Id: I20e3d6f11458f00ff75f32419b964c97635995b1
Test: TH needs to test
1 file changed