This reverts commit 4b8b650c.

Reason for revert: causes build failure on the Mac dEQP builder.

Original change's description:
> BUILD.gn: prepare dEQP test support on Mac
> 
> BUG=angleproject:1569
> 
> Change-Id: I77aa55d28b884fa648ff52aedddf3a23fe6e4a8c
> Reviewed-on: https://chromium-review.googlesource.com/713194
> Commit-Queue: Corentin Wallez <cwallez@chromium.org>
> Reviewed-by: Frank Henigman <fjhenigman@chromium.org>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>

TBR=fjhenigman@chromium.org,jmadill@chromium.org,cwallez@chromium.org

Change-Id: Idc08cf12294505600890d1c6e43f62c0261631a5
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: angleproject:1569
Reviewed-on: https://chromium-review.googlesource.com/741881Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>