Our lookup key for generated sampling functions was only using the
sampler and image view descriptors into account. The same descriptors
can be used in various different sampling instructions, so we need to
also make that part of the lookup key.

Bug: b/129523279
Change-Id: I325aa5571191e4ffc69214c2d13d431d21316fed
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/31949
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>