Move partial train MTS tests to presubmit

Move the MTS tests that are being run with partial train installs (only
NetworkStack+CaptivePortalLogin installed, or only Tethering installed)
to presubmit.

The tests have been passing in postsubmit.

Test: TH needs to test TEST_MAPPING change
Change-Id: Icc79fb430637e3fbf8e0ef2267aab1842a831915