[clang] [flang] [Flang-new][OpenMP] Add offload related flags for AMDGPU (PR #96742)

[Andrzej Warzyński via cfe-commits]

https://github.com/banach-space commented:

> fcuda-is-device flag is not used by Flang currently. In the future it will be needed for Flang equivalent functions: AMDGPUTargetCodeGenInfo::getGlobalVarAddressSpace AMDGPUTargetInfo::getTargetDefines .

I don't follow - why would anything related to CUDA be relevant here?

https://github.com/llvm/llvm-project/pull/96742