[wgpu-hal] With shader passthrough use given "binding" indices in Vulkan instead of incrementing from 0

[dylanblokhuis]

Is your feature request related to a problem? Please describe.
When using SPIR-V passthrough it can be very confusing when creating bind group layouts that the binding indices you pass in with BindGroupLayoutEntry, won't be the same internally in Vulkan, causing mismatches.

Describe the solution you'd like
Whenever the pipeline layout is given explicitly, use the given binding indices instead of using next_binding

Describe alternatives you've considered
Rewriting the SPIRV words to match the actual bindings created by wgpu, which isn't ideal.

[inner-daemons]

This is a me issue. Description of shader interface will be required in passthrough shaders, on all backends. I'm gonna work on this but it'll be a while.

[dylanblokhuis]

This is a me issue. Description of shader interface will be required in passthrough shaders, on all backends. I'm gonna work on this but it'll be a while.

Maybe not a perfect solution for the future but maybe already have something for the people using SPIRV with unsupported capabailities to expect the bindings to match? #9353

[inner-daemons]

@dylanblokhuis I mean yeah thats fine. But it just would be more complicated with non-spirv since they have different binding models that can't really be derived from just the pipeline layout info I think.