[lld] [llvm] [LTO][lld] Emit textual assembly code with '--save-temps' (PR #195922)

[Matt Arsenault via llvm-commits]

arsenm wrote:

> What changes exactly? Using MC is destructive so I don't think we can just re-use the existing one. Going from IR -> .s -> .o is possible but a much bigger change.

There are numerous cloning bugs, but it also doesn't even try to preserve everything. The main piece of hidden state which isn't preserved is uselistorder 

https://github.com/llvm/llvm-project/pull/195922