Enable exprs for GLSL binding layout qualifiers

[fairywreath]

Closes #5690, partially closes #2174.

Enable const integer literal expressions for GLSL set and binding layout qualifiers. This is only applied for set and binding qualifiers but this PR sets up a good foundation to also modify other GLSL layout qualifiers in the future. Additionally, this PR introduces a change to error out on unrecognized GLSL layout qualifiers instead of silently ignoring.

[csyonghe]

Looks good overall! Thank you for contributing the patch!

[csyonghe]

Instead of using name comparisons, just dynamic cast uncheckedAttr:

if (auto bindingAttr = as<UncheckedGLSLBindingLayoutAttribute>(uncheckedAttr))
{
     ...
}

[fairywreath]

Done for "binding" and "offset" but "set" and other glsl layout modifier names that will be added in the future do(or will) not have explicit types. Binding and offset explicitly have them just to work around the edge case for atomic counters.

[csyonghe]

May as well add a type for UncheckedGLSLSetLayoutAttribute and get rid of the name comparison here.

[fairywreath]

Yeah I will clean this up in another patch that implements the other GLSL layout modifiers to exprs. I originally did not want to add a new Unchecked AST modifier node for every modifier but this is indeed cleaner.

[csyonghe]

There are still some test regressions that need to be fixed.

[fairywreath]

layout(rgba6f) // image format not supported by slang
RWTexture2D<float4> texture;

This code does not compile because my change introduces errors on unknown qualifiers, including unsupported/unknown image formats. The current behavior silently ignores this - should I keep this behavior and at least introduce a warning?

EDIT: my latest change still enforces the error, do tell me if this is not preferred.

[csyonghe]

Looks good to me. Error on unknown qualifier is good.

[jkwak-work]

I am changing the label to be "pr: breaking change", because this change can cause errors on the user applications that were working fine before.