[llvm] [CodeGen] Add an option to skip extTSP BB placement for huge functions. (PR #99310)

[Rahman Lavaee via llvm-commits]

rlavaee wrote:

I think eventually, we should improve the algorithm to use a priority-queue for the best merge candidate (thereby O(1) for finding the best merge and O(lg n) for updates), but until then a knob is best we can have.

https://github.com/llvm/llvm-project/pull/99310