This patch add f16 types and their constructors and conversions in
resolver and intrinsic table. Also implement relating unit tests.
Bug: tint:1473, tint:1502
Change-Id: Ida1336193a72a73959e50e6a3eb12be44c0396b5
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/94642
Commit-Queue: Zhaoming Jiang <zhaoming.jiang@intel.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>