The Operand class is a low-level abstraction of rvalues and constants.
It should not carry the SPIR-V type ID. We only need the size in
components.

Bug: b/129000021
Change-Id: I6cb3ed6341b1ccf5ef759075d7410ba447617c8b
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/43693
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>