[llvm] [GlobalISel] Add G_BITCAST to computeKnownBits (PR #217841)

[Chinmay Deshpande via llvm-commits]

chinmaydd wrote:

I believe https://github.com/llvm/llvm-project/pull/216287 implements the same change. Please coordinate and lets move forward with one of them.

https://github.com/llvm/llvm-project/pull/217841