[llvm] [Inline] Allow inlining with null_pointer_is_valid mismatch (PR #190510)

[Miguel Ojeda via llvm-commits]

ojeda wrote:

I don't think `rustc` provides at the moment a way to set `null_pointer_is_valid` like `-fno-delete-null-pointer-checks`.

Also: https://internals.rust-lang.org/t/dereferenceable-zero/23991/71.

Cc @nbdd0121 @RalfJung 

https://github.com/llvm/llvm-project/pull/190510