[llvm] Add out-of-line-atomics support to GlobalISel (PR #74588)

[Pavel Iliin via llvm-commits]

https://github.com/ilinpv commented:

Overall outline atomics part looks good, for global-isel probably @davemgreen can provide some input. Thank you for bringing outline atomics there!

https://github.com/llvm/llvm-project/pull/74588