Removing duplicate definitions in ANGLE.

Bug: angleproject:5905
Change-Id: Ie62ad39a1ebc0d8b0d2c005723f461bc7309eade
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2889831Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>