This reverts commit e1ad9b89.

Reason for revert: Landed test that fails with GC stress

Original change's description:
> Fixes for size_t LookupIterator
> 
> Fixing some fallout from c968607e
> aka r65078
> 
> Bug: chromium:1026729,chromium:1026856,chromium:1026909,chromium:1026974
> Change-Id: I98a4466595fbf1635af403ab58842977882c0453
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1930907
> Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#65158}

TBR=jkummerow@chromium.org,mstarzinger@chromium.org,verwaest@chromium.org

Change-Id: I1f1e95d37b033e53330adae08071cbe34e1d9488
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:1026729, chromium:1026856, chromium:1026909, chromium:1026974
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1933599Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65159}