[clang] [NFC][LifetimeSafety] Add experimental_invalidates annotation (PR #186799)

[Gábor Horváth via cfe-commits]

Xazax-hun wrote:

Makes sense. I think some of the questions are:
* Do we want to treat every non-const functions as invalidating and have a special attribute for functions that are not doing invalidation instead?
* The one you bring up about partial invalidation and how to do that when the implementation details are private.


https://github.com/llvm/llvm-project/pull/186799