Boost remote-transition animator processes during animation

This basically ties applicationthread binder token to remote
transitions. Shell is first boosted (to run the shell transition
logic) and if it then delegates to a remotetransition, it will
then request that process also be boosted.

Bug: 183993977
Test: add logging in WPC.setRunningRemoteAnimation and verify calls
      during transitions
Change-Id: I94babc327e935ea81271942287a83b948dd11f8b