[clang] [Sema] Add check for bitfield assignments to integral types (PR #69049)

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vabridgers wrote:

> LGTM! Btw, if you're just repairing tests like you had to do here, you generally are okay to not go through another round of review unless you want an extra set of eyes on things. The original approval is fine so long as you're not making substantial changes to the code.

Thanks @AaronBallman ! 

https://github.com/llvm/llvm-project/pull/69049