Remove warning about f64->f32 cast being potential UB
Remove warning about f64->f32 cast being potential UB

As discussed in #15536, the LLVM documentation incorrect described
overflowing f64->f32 casts as being undefined behavior. LLVM never
treated them as such, and the documentation has been adjusted in
https://reviews.llvm.org/rL329065. As such, this warning can now
be removed.

Closes #49622.

graydon/rust,GBGamer/rust,graydon/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,GBGamer/rust,graydon/rust,graydon/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,aidancully/rust