mypy

bf1b7c8b - [mypyc] Support _benchmark test suffix for optimized run tests (#21047)

[mypyc] Support _benchmark test suffix for optimized run tests (#21047) If a mypyc run test has `_benchmark` in the test name as a suffix (not necessarily the final suffix), the test case will be compiled with optimizations enabled, and this also applies to `librt` if it needs to be built. The idea is that this can be used to easily run `librt` benchmarks by using temporary throwaway tests. Tested by manually running some test cases with and without a `_benchmark` suffix.