[HLSL][SPIRV] Implement vk::ext_builtin_input

[s-perron]

Implements the vk::ext_builtin_input attribute. See the Inline SPIR-V documentation.

The design for the implementation is https://github.com/llvm/wg-hlsl/blob/main/proposals/0019-spirv-input-builtin.md.

[Keenuts]

Fixed with #138530