fix: perform microtask checkpoint before MicrotaskRunner destruction

[ckerr]

Description of Change

Fix a bug that caused periodic test failures. Sample failure:

not ok 396 utilityProcess module stderr property is valid when child process launches with pipe stdio configuration
expected '' to equal 'world'
AssertionError: expected '' to equal 'world'
at Context. (electron/spec/api-utility-process-spec.ts:176:22)
at processTicksAndRejections (node:internal/process/task_queues:95:5)

The problem seems to be that the test spawned this script which wrote to stderr immediately before exiting and it was possible for there to still be pending queued tasks when NodeService destroyed the microtask runner.

The approach extracts the tell-v8-to-perform-a-checkpoint code from MicrotaskRunner::DidProcessTask() into a new public convenience function MicrotaskRunner::PerformCheckpoint(). It calls that function from JavascriptEnvironment::DestroyMicrotaskRunner() before destroying the microtask runner.

In main I'm able to trigger this test failure about 50% of the time. In this branch I wasn't able to break it in 100 iterations.

CC @deepak1556 who has done a lot of work in this code in #24131 and #34980 and @codebytere's CallbackScope code in #27001

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.

Release Notes

Notes: Fixed bug that could fail to process pending microtasks added to a child process immediately before calling process.exit().

[ckerr]

Looks like this change needs some work; it introduces a regression in

utilityProcess module lifecycle events emits 'exit' when there is uncaught exception

[deepak1556]

I like the change in this PR, however I am wondering if the following was also considered. Currently we drain pending macro tasks on the uv loop when the JavaScriptEnvironment is destroyed

electron/shell/browser/javascript_environment.cc

Line 122 in 713d8c4

platform_->DrainTasks(isolate_);

, if we did it before the microtask runner is destroyed it should trigger the checkpoints instead of us having to trigger it manually.

[codebytere]

@deepak1556 there are some contexts where we don't have a MicrotaskRunner (for ex. NodeMain) - are you suggesting we move the DrainTasks call out of the dtor or just duplicate it into JavascriptEnvironment::DestroyMicrotasksRunner()?

[deepak1556]

I am suggesting to move DrainTasks out of the dtor and call it before destorying the MicrotasksRunner in the browser and utility process, for other process move it to relevant places. Another reason to move this out would be, currently we don't terminate isolate during process exit so if the tasks were to enter JS we don't stop it from happening and having them run after environment destruction seems incorrect. I am also considering to mark the isolate for termination in the utility process due to a recent bug I started looking at.