Compiler::get_shader_resources() does not return all uniforms

[hiteshbosamiya]

I have the following uniforms in my fragment shader:

layout(location = 0) uniform mat4 u_model;
layout(location = 4) uniform mat4 u_view;
layout(location = 8) uniform mat4 u_projection;

There is no way to get the above uniforms using Compiler::get_shader_resources() method (the struct ShaderResources does not contain uniforms member). The ones which does not have base type SPIRType::Image, SPIRType::Sampler, SPIRType::SampledImage or SPIRType::AccelerationStructure are not getting collected, I think they should be collected as uniforms.

[hiteshbosamiya]

As per @HansKristian-Work, since the plain uniforms are supported only in legacy GL, we will use the name gl_plain_uniforms instead of uniforms. Created PR #2190.