[llvm] Reland "[LV]: Teach LV to recursively (de)interleave." (PR #125094)

[Hassnaa Hamdi via llvm-commits]

hassnaaHamdi wrote:

I have reverted the commit that was doing bail-out for interleaving.
I think this patch now is ready for landing once #125434 gets landed.

https://github.com/llvm/llvm-project/pull/125094