This reverts commit fefd9230.

Reason for revert: breaks no-i18n 
https://ci.chromium.org/p/v8/builders/luci.v8.ci/V8%20Linux%20-%20noi18n%20-%20debug/23279

Original change's description:
> [ia32,root] Disable root indirections in irregexp code
> 
> Irregexp code spills and restores ebx at boundaries, and clobbers it
> inbetween. Root-relative loads are disabled in this region.
> 
> Bug: v8:6666
> Change-Id: I9c68bc8ef88d324da609996a8457ac9e30a9b6fc
> Reviewed-on: https://chromium-review.googlesource.com/c/1280762
> Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
> Commit-Queue: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#56639}

TBR=sigurds@chromium.org,jgruber@chromium.org

Change-Id: I1a349874c28218442ebed4f127d23d69dff094cd
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: v8:6666
Reviewed-on: https://chromium-review.googlesource.com/c/1280225Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56643}