This patch make SPIRV writer support emitting f16 types, f16 literals,
f16 constructor and convertor. Unittests are also implemented.
Currently SPIRV writer will require 4 capabilities in generated SPIRV:
`Float16`, `UniformAndStorageBuffer16BitAccess`,
`StorageBuffer16BitAccess`, and `storageInputOutput16`.
Bug: tint:1473, tint:1502
Change-Id: Ia1af04f1f4a02bf1b1c2599a5d89791854eabc16
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/95920
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Zhaoming Jiang <zhaoming.jiang@intel.com>
66d4f6e6fb