This reverts commit 6e27386d.

Reason for revert: There will be another much simpler and
back-mergeable fix.

Original change's description:
> Reland "[runtime] Add shortcuts for elements kinds transitions."
> 
> This is a reland of b90e83f5
> Original change's description:
> > [runtime] Add shortcuts for elements kinds transitions.
> >
> > 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}
> 
> Bug: chromium:738763, chromium:742346, chromium:742381, chromium:745844
> Change-Id: I93974e3906b2c7710bd525f15037a2dd97f263ad
> Reviewed-on: https://chromium-review.googlesource.com/575227
> Commit-Queue: Igor Sheludko <ishell@chromium.org>
> Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
> Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#46759}

TBR=ulan@chromium.org,jkummerow@chromium.org,ishell@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:738763, chromium:742346, chromium:742381, chromium:745844
Change-Id: I203dc748c47db554e0a86d61f0e2b7b8b96f2370
Reviewed-on: https://chromium-review.googlesource.com/581547
Commit-Queue: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46826}