Introducing a TF_BUILTIN macro that wraps CodeStubAssembler usage
into a convenient interface (using a subclass under the hood).

No changes since previous attempt; this was only reverted because it blocked another revert.
Original review: https://codereview.chromium.org/2517833005/

TBR=ishell@chromium.org

Review-Url: https://codereview.chromium.org/2529373002
Cr-Commit-Position: refs/heads/master@{#41315}