Was incorrect and causing a Clang warning.

Bug: chromium:992863
Change-Id: Ieff7b332ee11a6330bd5879d73b53ad374f40664
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1751622Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>