Implements the following opcodes:
• OpGroupNonUniformShuffleUp
• OpGroupNonUniformShuffleDown

Bug: b/133510501
Tests: dEQP-VK.subgroups.*
Change-Id: Ia0c8b3f90b9247e7052c287601e110107dbaa17e
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/35090
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Chris Forbes <chrisforbes@google.com>
Tested-by: Ben Clayton <bclayton@google.com>