spirv: handle OpCopyObject correctly with any types

spirv: handle OpCopyObject correctly with any types

This implements OpCopyObject as a blind copy and propagates the
access mask properly even if the source object type isn't a SSA
value.

This fixes some recent dEQP-VK.descriptor_indexing.* failures
since CTS changed and now apply nonUniformEXT after constructing
a combined image/sampler.

Original patch is from Jason Ekstrand.

Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4909>