[llvm] [coro][pgo] Remove redundant coroutine test files (PR #89620)

[Yuxuan Chen via llvm-commits]

yuxuanchen1997 wrote:

Are there any lit tricks to make it read from the equivalent tests under `Transforms/Coroutines` directory instead of `%s`? So that we only have one copy of the test, but still give you notifications for PGO team. 

https://github.com/llvm/llvm-project/pull/89620