[llvm] Overhaul the TargetMachine and LLVMTargetMachine Classes (PR #111234)

[Nikita Popov via llvm-commits]

nikic wrote:

@matinraayai You'll have to open a new PR on top of main for that, it's not possible to push commits to a PR that has been merged.

https://github.com/llvm/llvm-project/pull/111234