[llvm] [Thumb] Resolve FIXME: Transform "(and (shl x, c2), c1)" into "(shl (and x, c1>>c2), c2)" (PR #82120)

[Tim Northover via llvm-commits]

TNorthover wrote:

I think this one looks reasonable to me. Logic seems to check out and it looks for benefits before proceeding.

https://github.com/llvm/llvm-project/pull/82120