[llvm] [BDCE] Handle multi-use `select` of `and`s on demanded bits (PR #79688)

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

> I would expect you to query the demanded bits of the and instruction, similar to the code directly above that handles sext. Unless I'm missing something, that will cover the motivating pattern.

Reviewed, thanks, somehow I thought it would be easier to handle the `and`/`or` as operands of the instruction being analyzed (and get its current demanded bits).

https://github.com/llvm/llvm-project/pull/79688