Use the same naming convention as other similar formats.

Bug: angleproject:5731
Change-Id: I187881f4bc4691a0963502ed41f42ab0ebf4171c
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2846824Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Alexey Knyazev <lexa.knyazev@gmail.com>