Fix gn check on iOS for dEQP and trace targets
Fix gn check on iOS for dEQP and trace targets

Bug: angleproject:5417
Change-Id: I0e445eb4c5f3a88fbaea4599fa3d2f87b8632fb5
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2665267
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Commit-Queue: Yuly Novikov <36f5580f63d0a3eacc17e89a61d11e2f646630d2@chromium.org>

ppy/angle,ppy/angle,ppy/angle,ppy/angle