[clang] [CIR][NFC] Add LLVM and OGCG checks to global-var-simple.cpp (PR #191521)

[Andy Kaylor via cfe-commits]

https://github.com/andykaylor commented:

Does this test even add anything to `clang/test/CIR/CodeGen/globals.cpp`? We should probably just delete it. The tests at this level were added very early when we were just trying to get things wiggling. I don't think they're needed now.

https://github.com/llvm/llvm-project/pull/191521