Add a primitive linalg-lower-to-llvm-dialect pass

    This CL builds upon ftynse@'s Linalg dialect conversion (in examples/Linalg/Linalg1) and updates it to support buffers and the fully composed form of view and slice operations.
    A new BufferSizeOp is introduced for the purpose of extracting the size information from a buffer.
    This will be useful in a followup CL for an end-to-end LLVM execution path where mlir-cpu-runner will allocate a buffer.

--

PiperOrigin-RevId: 246358593