Allow more execArgv flags to be passed to workers

[adriencaccia]

Clear and concise description of the problem

I need to pass execution flags to the workers to fully support vitest on CodSpeed (more details below). At this time, execution flags are all filtered out except --cpu-prof and --heap-prof.
The flags are described here: https://github.com/CodSpeedHQ/codspeed-node/blob/707a076f6178125fa1042f4a4decd51d11b03b56/packages/core/src/introspection.ts#L5-L21

Suggested solution

It is a touchy subject that can lead to bugs as already stated in the code comment below and in #2702.
I would propose some kind of escape hatch for library authors where we can remove the filtering entirely. Using a specific env variable for example.

The change would need to be done in

vitest/packages/vitest/src/node/pool.ts

Lines 63 to 67 in 29299f3

	// Instead of passing whole process.execArgv to the workers, pick allowed options.
	// Some options may crash worker, e.g. --prof, --title. nodejs/node#41103
	const execArgv = process.execArgv.filter(execArg =>
	execArg.startsWith('--cpu-prof') || execArg.startsWith('--heap-prof'),
	)

Alternative

Expose an option directly in vitest config, to specify the flags to be passed to the workers.

Additional context

I am working on adding first class vitest support to CodSpeed, I started the work at CodSpeedHQ/codspeed-node#26. In order to have automated flame graphs with each benchmark, we need to pass a few additional v8 args to the workers.
I managed to get it working with a patch of vitest removing the filtering.

With pool: 'forks', all the flags needed by CodSpeed are working, as this job is working https://github.com/CodSpeedHQ/codspeed-node/actions/runs/6668657521/job/18124687199.

However, I tested it with the default pool: 'threads' and got an error because one of the flags was not supported, highlighting that allowing all flags for every pool method is definitely not the way to go.

I would gladly do a PR if and when we agree on what API to expose 😃

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[sheremet-va]

Maybe we can expose a way to pass down execArgs in poolOptions.{threads,forks,vmThreads}?

[adriencaccia]

Yep that would work for me!