[llvm] [llvm] Drop "const" from "const ArrayRef" (NFC) (PR #138818)

[Kazu Hirata via llvm-commits]

kazutakahirata wrote:

> LGTM but this is not specific to ArrayRef, it is just a special case of const return type: https://clang.llvm.org/extra/clang-tidy/checks/readability/const-return-type.html

Thanks for the review!  Yes, I've in fact generated this patch (and its friends) with clang-tidy and been splitting it for easier reviews.  The entire result of `readability-const-return-type` would be too big for one PR (even just for `llvm/`), often with function declaration changes and definition changes spread apart.


https://github.com/llvm/llvm-project/pull/138818