[SPIRV] Implement LLVM IR and backend for typed buffer counters (#161425)

This commit implements the backend portion of the typed buffer counter
proposal described in
https://github.com/llvm/wg-hlsl/blob/main/proposals/0023-typed-buffer-counters.md.
This is the second part of the implementation, focusing on the LLVM IR
and SPIR-V backend.

Specifically, this commit implements the "LLVM IR Generation and Backend
Handling"
section of the proposal. This includes:
- Adding the `llvm.spv.resource.counterhandlefromimplicitbinding` and
  `llvm.spv.resource.counterhandlefrombinding` intrinsics.
- Implementing the selection of these intrinsics in the SPIRV backend to
  generate the correct `OpVariable` and `OpDecorate` instructions for
  the counter buffer.
- Handling `IncrementCounter` and `DecrementCounter` via a new
  `llvm.spv.resource.updatecounter` intrinsic, which is lowered to
  `OpAtomicIAdd`.
- Adding a new test file to verify the implementation.

Contributes to https://github.com/llvm/llvm-project/issues/137032

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Co-authored-by: Marcos Maronas <marcos.maronas@intel.com>