Update all uses of variadic `.Cases` to use the initializer list
overload instead. I plan to mark variadic `.Cases` as deprecated in a
followup PR.

For more context, see https://github.com/llvm/llvm-project/pull/163117.

See https://github.com/llvm/llvm-project/pull/147168 for more info.

These are identified by misc-include-cleaner.  I've filtered out those
that break builds.  Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.

This change allows to expose through an interface attributes wrapping
content as external resources, and the usage inside the ModuleToObject
show how we will be able to provide runtime libraries without relying on
the filesystem.

This is a follow-up of #117246.

I thought then it would be easy to edit a DictionaryAttr but it turns
out that these attributes are immutable and need to be passed during the
construction of the gpu.binary Op.

The first commit was using the NVVMTargetAttr to pass the information.
After feedback from @fabianmcg, this PR now passes the information
through a new option of the gpu-module-to-binary pass.

Please add reviewers, as you see fit.

This patch adds an argument to `gpu::TargetAttrInterface::createObject`
to pass the GPU module. This is useful as `gpu::ObjectAttr` contains a
property dict for metadata, hence the module can be used for extracting
things like the symbol table and adding it to the property dict.

---------

Co-authored-by: Oleksandr "Alex" Zinenko <ftynse@gmail.com>

Most of the code here does not depend on the NVPTX target. In particular
the simple offload can just emit LLVM IR and we can use this without the
NVVM backend being built, which can be useful for a frontend that just
need to serialize the IR and leave it up to the runtime to JIT further.

LLVM_HAS_NVPTX_TARGET is automatically set depending on whether NVPTX
was enabled when building LLVM. Use this instead of manually defining
MLIR_ENABLE_CUDA_CONVERSIONS (whose name is a bit misleading btw).

This patch removes the `offloadingHandler` option from the
`ModuleToBinary` pass. The option is removed as it cannot be parsed from
textual form.

This fixes issue #90344.

This is a follow up of #83004, which made the same change for
`MLIR_CUDA_CONVERSIONS_ENABLED`. As the previous PR, this PR commit
exposes mentioned CMake variable through `mlir-config.h` and uses the
macro that is introduced with the same name. This replaces the macro
`MLIR_ROCM_CONVERSIONS_ENABLED`, which the CMake files previously
defined manually.