[clang] [Clang] Allow all address spaces to be converted to the default (PR #112248)

[Matt Arsenault via cfe-commits]

arsenm wrote:

> They should not "just work" if you're compiling for vanilla C/C++ (so not CUDA C++, or SYCL, or OpenCL C/C++ etc.) because neither of those defines such a notion.

a6a237f2046ad8993db30481c8b61aeb2f73a5ad added an explicit addrspace_cast operator. It would be better to use something like this rather than just freely enabling any implicit cast 

https://github.com/llvm/llvm-project/pull/112248