Fix glClearColor calls to use GLColor32F constants. Bug: angleproject:5025 Change-Id: I8d8bc8ff0b93951e19697d57c07368e1196498ae Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3499564 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>