[llvm] [TailDuplicator] Add maximum predecessors and successors to consider tail duplicating blocks (PR #78582)

[via llvm-commits]

alexfh wrote:

Benchmark compiled with clang after this commit with `-mllvm=-tail-dup-pred-size=64 -mllvm=-tail-dup-succ-size=64` has no regression compared to before this commit. I'm running with 32 just in case. Also note that this benchmark is in no way considered representative of any real workloads we care about. 

https://github.com/llvm/llvm-project/pull/78582