Revert of Simplify and compact transitions storage (patchset #4 id:80001 of https...

Revert of Simplify and compact transitions storage (patchset #4 id:80001 of https://codereview.chromium.org/980573002/)

Reason for revert:
x64 test failures

Original issue's description:
> Simplify and compact transitions storage
>
> Simple transitions are now stored in a map's "transitions" field (as a WeakCell wrapping the target map); full TransitionArrays are used when that's not sufficient.
> To encapsulate these storage format implementation details, functions for manipulating and querying transitions have been refactored to be static functions on the TransitionArray class, and take maps as inputs.
>
> Committed: https://crrev.com/45fbef7f2252fce10634931cb103ccc1fc95ae6a
> Cr-Commit-Position: refs/heads/master@{#27029}

TBR=verwaest@chromium.org,ulan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/982143002

Cr-Commit-Position: refs/heads/master@{#27030}