Revert of [builtins] Also port the Object.prototype.__proto__ accessors to C++. (patchset #1 id:1 of https://codereview.chromium.org/2417183002/ )

Reason for revert:
[Sheriff] Speculative revert for webkit tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/10656

Was broken before, but this one test failure started with this CL:
inspector/console/console-dir.htm

All other errors stopped after another revert.

See also:
https://github.com/v8/v8/wiki/Blink-layout-tests

Original issue's description:
> [builtins] Also port the Object.prototype.__proto__ accessors to C++.
>
> These accessors also always call into C++ anyways, so there's no point
> in having the JavaScript wrappers.
>
> R=yangguo@chromium.org
> BUG=v8:5049
>
> Committed: https://crrev.com/ede69cfabd790fe9f171b5d1f426ea0fc55e3c98
> Cr-Commit-Position: refs/heads/master@{#40298}

TBR=yangguo@chromium.org,bmeurer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:5049

Review-Url: https://codereview.chromium.org/2415173003
Cr-Commit-Position: refs/heads/master@{#40303}