Fix performance_report when used with %%time or %%timeit magic

[eriknw]

• Closes Performance report Calling Code wrong when using %%time  #5459
• Tests added / passed--It's not obvious how to add tests for this.
• Passes pre-commit run --all-files

This takes a narrow approach and only attempts to handle when performance_report is used within %%time and %%timeit magics.

[fjetter]

FWIW we have another function which tries to determine the code without explicit stacklevel, see

distributed/distributed/client.py

Line 2522 in 7193bb9

def _get_computation_code() -> str:

I'm wondering if this would work for this problem and we can reuse

[eriknw]

@fjetter I gave client._get_computation_code a try and it seems to work.

My concern with using it though is that the stacklevel argument is user-facing in performance_report and is now ignored. Exposing stacklevel allows users to create their own context managers or functions that can use performance_report.

I think I'll add stacklevel as an optional argument to client._get_computation_code.

[eriknw]

I think this is ready. The test failures appear unrelated. CC @ncclementi

[fjetter]

Thank you @eriknw !