This reverts commit e816d2ba.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> [heap] Turn on --write-protect-code-memory.
> 
> Bug: chromium:774108
> Change-Id: Ifcf9939f29c9a3dc14ed686dc14608860ff32678
> Reviewed-on: https://chromium-review.googlesource.com/950902
> Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
> Reviewed-by: Michael Hablich <hablich@chromium.org>
> Commit-Queue: Hannes Payer <hpayer@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#51766}

TBR=mstarzinger@chromium.org,hpayer@chromium.org,hablich@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:774108
Change-Id: Icf6da14ec795cf89d2c4085ff7f9afb892184c12
Reviewed-on: https://chromium-review.googlesource.com/955692Reviewed-by: Hannes Payer <hpayer@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#51840}