[flang-commits] [flang] [flang] Change `uniqueCGIdent` separator from `.` to `_` (PR #71338)

[Slava Zakharin via flang-commits]

vzakhari wrote:

@fabianmcg, can you please clarify if it is a requirement that in the final host and device "images" the variables are named the same way? Will there be any `RegisterVar` call in the host code that takes the variable's device name?

https://github.com/llvm/llvm-project/pull/71338