Switch to use framework/junit-host.jar

Ran the tests individually and most passed, a couple did not.
They were 115-merge and 119-merge-conflict. They both failed
with "unsupported class file version 52.0" failures so nothing
to do with this change.

Bug: 30188076
Test: ran them with ./run-test.
Change-Id: I21f9ea34e27972c5195e6feaa96763a960d04d4e