Add benchmarks for sync/async/sync*/async* calls.

[mkustermann]

This issue goes together with issues increasing the performance, e.g.

• Faster async stacks
• Faster sync*

Related issues:

• the performance of async and await syntax are quite slow #29189
• Async: "await for" vs. "listen()" performance #23645
• Sync* methods are too slow. #32102

[mkustermann]

@lrhn

[mkustermann]

The benchmarks were added in 1fcaa26