[clang] [clang][Sema] Make lifetime annotations non-type attributes (PR #196549)

[Aaron Ballman via cfe-commits]

https://github.com/AaronBallman commented:

Thank you! I'm roughly in favor of this but am concerned that zero tests broke. I would expect any test like:
```
struct S {
  void func() [[clang::lifetimebound]];
};
```
to break because it's no longer a valid type attribute. Is all of our test coverage using `__attribute__` instead? Or perhaps it's using only the declaration form of the attribute?

https://github.com/llvm/llvm-project/pull/196549