[llvm] [CodeGen][NPM] Update BranchFolderLegacy make tail merge configurable via flag (PR #135277)

[Mikhail R. Gadelha via llvm-commits]

https://github.com/mikhailramalho commented:

@arsenm this is a tentative patch do address your comments.

I do have a couple of questions:

https://github.com/llvm/llvm-project/pull/135277