This reverts commit e0b76c9a.

Reason for revert: Changes layout tests:
https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/18522

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

Original change's description:
> Add fast path to ObjectGetOwnPropertyDescriptor
> 
> Bug: v8:6557
> Change-Id: I384e9f36058c73d40be1faf5ae1bf8c01d068f0e
> Reviewed-on: https://chromium-review.googlesource.com/682059
> Commit-Queue: Maya Lekova <mslekova@google.com>
> Reviewed-by: Igor Sheludko <ishell@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#48166}

TBR=ishell@chromium.org,mslekova@google.com

Change-Id: I27aa52786f79dd617faea6336df684821c1720d2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6557
Reviewed-on: https://chromium-review.googlesource.com/685314Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48171}