Adding a dependency on a module that has already had a TransitionMutator
run on it may require adjusting the variation name based on the results
of IncomingTranstion. Store the variants that existed before the
TransitionMutator ran, find one that is a subset of the requested
variant, and call TranstionMutator.IncomingTransition to update the
value.
Bug: 319288033
Test: TestPostTransitionDeps
Change-Id: I690357f9792401a3edbc5ae9fdcb666495954fbc
