[clang] [CIR] Lowering to LLVM for global pointers (PR #125619)

[Andy Kaylor via cfe-commits]

andykaylor wrote:

@lanza @bcardosolopes Do you want to look this over before I commit it? This change introduces some restructuring that I'll want to incorporate in the incubator, where it will have a somewhat bigger impact, so I'd like to get your buy-in or objections now before I start working on that incubator change. Thanks.

https://github.com/llvm/llvm-project/pull/125619