Only enable addAndTrueToLoopCondition feature on Mac Intel
Only enable addAndTrueToLoopCondition feature on Mac Intel

The issue which reported the need for this workaround only found a
problem on Mac. The failure doesn't happen on other the Linux
OpenGL Intel driver, so it shouldn't be enabled there.

Bug: chromium:1021900, chromium:644669
Change-Id: I65e7462828419aeb9182898f73977ee1c5e72ff3
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1904291
Reviewed-by: Kenneth Russell <1ebccd90c2bc76de65b6f830f2128a91ed69fdfb@chromium.org>
Reviewed-by: Geoff Lang <b6fc25fe0362055230985c05cbfa8adb741ccc0f@chromium.org>
Commit-Queue: Austin Eng <7866475962f30d05c6be99ab4f8ad1431d92209f@chromium.org>

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