[llvm] [InlineFunction] Use MDNode::getDistinct to reduce ScopedAlias MD clone time (PR #218817)

[Nikita Popov via llvm-commits]

nikic wrote:

I'm a bit skeptical about this. Semantically, the scope lists (unlike the scopes themselves) are not distinct, and if there are two identical scope lists, we want them to be deduplicated. Even if not during inlining itself, I think we can end up with duplicate scope lists lateron.

https://github.com/llvm/llvm-project/pull/218817