[llvm] [RISCV] Implement tail call optimization in machine outliner (PR #115297)

[Paul Kirth via llvm-commits]

https://github.com/ilovepi approved this pull request.

Other than @topperc's comments this seems good, modulo a few small nits w.r.t. formatting. Thanks for working on this! 😄 

https://github.com/llvm/llvm-project/pull/115297