[clang] [Attributes] Support Attributes being declared as only supporting late parsing when passing an experimental feature flag (PR #88596)

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Sirraide wrote:

> Given that a subsequent patch will add the necessary test coverage and the above problems I think it is reasonable for explicit tests for `LateAttrParsingExperimentalOnly` to be omitted

Yeah, if it’s not used anywhere or if both prs are merged at the same time, then that seems fine; as I said, I’m not too familiar w/ the overall context around this unfortunately.

https://github.com/llvm/llvm-project/pull/88596