This is a reland of 47b3db22
Original change's description:
> Vulkan: Let shader use rotation specialized constant
>
> If use rotation specialized constant is enabled via compiler options,
> this CL will use rotation specialized constant to generate flipXY,
> rotation matrix and negFlipXY. This allows the driver to optimize for
> the minimum instructions for rotation.
>
> Bug: b/171750979
> Change-Id: I9851ac999d4d35b9f230f796e5445bca0dcb1e77
> Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2514773
> Commit-Queue: Charlie Lao <cclao@google.com>
> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
> Reviewed-by: Ian Elliott <ianelliott@google.com>
> Reviewed-by: Jamie Madill <jmadill@chromium.org>
> Reviewed-by: Tim Van Patten <timvp@google.com>
Bug: b/171750979
Change-Id: I9efde40eb138bacb161cce483a30ec01fee0983b
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2533933
Commit-Queue: Charlie Lao <cclao@google.com>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
