Includes fast paths in the runtime for
DictionaryElementsAccessor, FastSmiOrObjectElementsAccessor,
FastDoubleElementsAccessor, TypedElementsAccessor, and
SloppyArgumentsElementsAccessor.

BUG=

Review-Url: https://codereview.chromium.org/2232063002
Cr-Commit-Position: refs/heads/master@{#38800}