Add "subgroup-size-control" feature

[Jiawei-Shao]

This patch adds the "subgroup-size-control" feature in gpuweb/gpuweb#5578.

[Jiawei-Shao]

@kainino0x @Kangz PTAL, thanks!

[Jiawei-Shao]

Hi @kainino0x and @Kangz ,

I cannot add subgroup-size-control because it hasn't been added to WebGPU SPEC and now CI requires the generated file must be up-to-date with gpuweb submodule.

[Kangz]

Let's not merge this before the feature is added to the spec, we can use Typescript casts to coerce the string into the enum type and temporarily bypass the typechecks when writing the CTS.

[kainino0x]

I cannot add subgroup-size-control because it hasn't been added to WebGPU SPEC and now CI requires the generated file must be up-to-date with gpuweb submodule.

The generated file is meant to be purely generated, never edited manually. You only need to edit the dist file and let them be out of sync. (that's why we have both)

Let's not merge this before the feature is added to the spec, we can use Typescript casts to coerce the string into the enum type and temporarily bypass the typechecks when writing the CTS.

Generally I recommend changing types during the experimental phase, because writing CTS using typescript casts on things like experimental dictionaries and new methods is a pain. However in this case the amount of casting is trivial and wouldn't significantly complicate the tests. So, I'm fine either way.