Don't duplicate anonymous lifetimes for async fn in traits
`record_lifetime_params_for_async` needs to be called outside of the scope of the function, or else it'll end up collecting anonymous lifetimes twice (those on the function and those within the `AnonymousCreateParameter` rib). This matches how `record_lifetime_params_for_async` is being used for functions with bodies below.
This fixes (partially) #110963 when the lifetimes are late-bound, but does not do so when the lifetimes are early-bound (as seen from the known-bug that I added).
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