[llvm] [NewPM][CodeGen] Refactoring CodeGenPassBuilder (PR #89708)

[via llvm-commits]

paperchalice wrote:

Now derived class should use `addModulePass`, `addFunctionPass`, `addMachineFunctionPass` to add custom passes properly.
I recalled that `ShadowStackGCLoweringPass` is converted to module pass, because it indeed modified the module by adding some global variables and new pass manager is designed for future pass concurrency. It looks like it must happens after `GCLoweringPass` because it handles `gc_root` related initializers.

https://github.com/llvm/llvm-project/pull/89708