[llvm] Reland [BasicBlockUtils] Handle funclets when detaching EH pad blocks (PR #159379)

[Gábor Spaits via llvm-commits]

spaits wrote:

Thank you @rnk .
- I have removed the unnecessary `make_early_inc_range`.
- I have moved `UniqueEHRetBlocksToDelete` a bit higher in scope and call `clear` on it before usage. (Maybe this way we can save some memory usage, probably the compiler would optimize this anyway :) ).
- Run `check-llvm-transforms` and `check-llvm-codegen` test suites with ASan for targets `RISC-V`, `X86` and `WebAssembly`.

https://github.com/llvm/llvm-project/pull/159379