[mlir][spirv] Add support for dense_resource in arith to spirv (#91318)

This adds support for `dense_resource` in arith to spirv. 

Note that this inlines the blob into the IR. Another possibility would
be to add proper dense_resource support to spirv, but there is a lot of
special handling going on to convert a `DenseElementsAttr` to the
correct SPIRV type. Some of that even iterates over all the values in
the Attribute. For proper support of a `DenseResourceElementsAttr` this
probably needs a redesign. I would like to hear some opinions on that!

The test is disabled on non little Endian machines. See
https://github.com/llvm/llvm-project/issues/63469 for more information.