[clang-tools-extra] [clang-tools-extra] Apply modernize-use-string-view to the code (PR #179514)

[Paul Kirth via cfe-commits]

ilovepi wrote:

> > Thanks for your feedback. So 1) Remove any non-clang-tidy files from this PR and 2) create separate PRs for all other products?
> 
> Sound good to me, we can merge this with only clang-tidy changes.

When you merge, be sure to update the title to use the tag `[clang-tidy]` if it will only have changes for that tool. I always forget that I cant fix it up with git, so you'll have to edit the title in the github UI. 

https://github.com/llvm/llvm-project/pull/179514