This is a reland of f5d30851

Original change's description:
> [builtins] Introduce further constant & external reference indirections
>
> This introduces further indirections for embedded constants and
> external references for builtins generated by the macro-assembler.
> The used mechanisms (LookupConstant and LookupExternalReference) are
> identical to what we already use in CSA.
>
> Almost all builtins are now isolate-independent in both release and
> debug modes. snapshot_blob.bin is roughly 670K smaller in embedded
> builds vs. non-embedded builds, while libv8.so is roughly 280K larger.
>
> Bug: v8:6666
> Change-Id: I7a6c2193ef5a763e6cf7543dd51597d6fff6c110
> Reviewed-on: https://chromium-review.googlesource.com/1006581
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#52810}

TBR=mstarzinger@chromium.org

Bug: v8:6666
Change-Id: I73dfe207f2c5f79a9a06c165c75f5619e88a5a17
Reviewed-on: https://chromium-review.googlesource.com/1030550Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52819}