[clang] [clang] apply clang-tidy's llvm-redundant-casting (NFC) (PR #191322)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

> 2 weeks seems like a long time these days, but that all is otherwise completely reasonable/appropriate/what I think too.
> 
> To be clear, your comment above is the TAGGING you mean, yes? If so, 2 weeks or so from now is long but not unreasonable.

If the work could change substantially, I could see it being reasonable to wait for two weeks from approval. But I don't expect significant changes to the patch between now and when it gets approved, so I think two weeks from *now* is reasonable lead time. 

https://github.com/llvm/llvm-project/pull/191322