The shortcuts ensure that field type generalization is properly
propagated in the transition graph.

Bug: chromium:738763
Change-Id: Id701a6f95ed6ea093c707fbe0bac228f1f856e9f
Reviewed-on: https://chromium-review.googlesource.com/567992
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46622}