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>