3047: Update async unsafe fn ordering in parser r=matklad a=kiljacken
As of rust-lang/rust#61319 the correct order for functions that are both unsafe and async is: `async unsafe fn` and not `unsafe async fn`.
This commit updates the parser tests to reflect this, and corrects parsing behavior to accept the correct ordering.
Fixes#3025
Co-authored-by: Emil Lauridsen <mine809@gmail.com>