[llvm] [ADT] Add TrieRawHashMap (PR #69528)

[David Blaikie via llvm-commits]

dwblaikie wrote:

Per https://llvm.org/docs/GitHub.html#updating-pull-requests it'd be helpful to, "When updating a pull request, you should push additional “fix up” commits to your branch instead of force pushing. This makes it easier for GitHub to track the context of previous review comments. Consider using the [built-in support for fixups](https://git-scm.com/docs/git-commit#Documentation/git-commit.txt---fixupamendrewordltcommitgt) in git."

(like, I can't readily tell what things changed in your most recent update - so I can see if/how different feedback was/wasn't addressed)

(I know we're all learning how to do pull requests in LLVM - I still haven't sent any of my own out... so I'm certainly no expert at making them, but I'm slowly learning what makes them easier/harder to review, at least)

https://github.com/llvm/llvm-project/pull/69528