This reverts commit da607264.

Reason for revert: Looked wrong. The persistent layout test
failures started in the next revision. The failure on the revision
of the reverted CL was just a flake.

Original change's description:
> Revert "Fix GCC 7 build errors"
> 
> This reverts commit c0f1ff24.
> 
> Reason for revert: Speculative revert for layout test timeout:
> https://build.chromium.org/p/client.v8.fyi/builders/V8-Blink%20Linux%2064/builds/16402
> 
> Original change's description:
> > Fix GCC 7 build errors
> > 
> > BUG=chromium:691681
> > R=​franzih@chromium.org
> > 
> > Change-Id: Id7e5698487f16dc217a804f6d3f24da7213c72b9
> > Reviewed-on: https://chromium-review.googlesource.com/530227
> > Commit-Queue: Toon Verwaest <verwaest@chromium.org>
> > Reviewed-by: Toon Verwaest <verwaest@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#46045}
> 
> TBR=adamk@chromium.org,franzih@chromium.org,mic.besace@gmail.com,verwaest@chromium.org
> 
> Change-Id: I2119a87a95ed9eb88b7b32ae436edf28dfc86c16
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: chromium:691681
> Reviewed-on: https://chromium-review.googlesource.com/541227
> Reviewed-by: Michael Achenbach <machenbach@chromium.org>
> Commit-Queue: Michael Achenbach <machenbach@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#46065}

TBR=adamk@chromium.org,machenbach@chromium.org,franzih@chromium.org,mic.besace@gmail.com,verwaest@chromium.org

Change-Id: Ieee7f6b3b80d380e720206e7b43c4b580918b1d7
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: chromium:691681
Reviewed-on: https://chromium-review.googlesource.com/541228Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46067}