This CL adds const-eval for `sin` and `sinh`.
Bug: tint:1581
Change-Id: I96345378c826e2c49ffae688b5185764019967d5
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/109560
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>