Rollup merge of #102642 - bryangarza:afit-tests, r=compiler-errors

Add tests for static async functions in traits

This patch adds test cases for AFIT, the majority of which are currently expected to run as `check-fail`.

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Note: I grabbed the cases from https://hackmd.io/SwRcXCiWQV-WRJ4BYs53fA

Also, I'm not sure if the `async-associated-types2` and `async-associated-types2-desugared` are correct, I modified them a bit from the examples in the HackMD.