deps: cherry-pick 79aee39 from upstream v8

This is a chery-pick if you consider reducing the context to -C2
a cherry-pick; WordIsSmi has been renamed to TaggedIsSmi upstream.

Original commit message:

    [builtins] Fix pointer comparison in ToString builtin.

    This fixes the bogus {Word32Equal} comparison in the ToString
    builtin implementing Object.prototype.toString to be a pointer-size
    {WordEqual} comparison instead. Comparing just the lower half-word
    is insufficient on 64-bit architectures.

    R=jgruber@chromium.org
    TEST=mjsunit/regress/regress-crbug-664506
    BUG=chromium:664506

    Review-Url: https://codereview.chromium.org/2496043003
    Cr-Commit-Position: refs/heads/master@{#40963}

Fixes: https://github.com/nodejs/node/issues/12411
PR-URL: https://github.com/nodejs/node/pull/12412


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>