fix: collect coverage using node inspector (fix #378)

[Demivan]

Fixes #378

For now this is just a proof of concept.
Tested on fluent-vue and vitest reports incorrect coverage for it. With detailed coverage enabled it is much better now.
It still reports wrong code lines though.

edit:

Coverage is almost the same as it would be if Vitest waited for all coverage files to finish writing to disk. Tested on fluent-vue.

With "wait for coverage to be written" fix:

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	93.55	92.66	86.84	93.55
src	93.64	96.92	88	93.64
TranslationContext.ts	100	100	100	100
composition.ts	100	100	100	100
getContext.ts	100	94.73	100	100	27
index.ts	80.41	90	72.72	80.41	65-83
inheritBundle.ts	100	100	100	100
symbols.ts	100	100	100	100
src/util	100	80	100	100
camelize.ts	100	100	100	100
warn.ts	100	66.66	100	100	7
src/vue	92.82	87.17	81.81	92.82
component.ts	100	100	100	100
directive.ts	88.8	81.48	75	88.8	52-55,98-107

This implementation:

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	95.5	87.87	91.66	95.5
src	93.64	95.23	88	93.64
TranslationContext.ts	100	100	100	100
composition.ts	100	100	100	100
getContext.ts	100	91.66	100	100	27
index.ts	80.41	88.88	72.72	80.41	65-83
inheritBundle.ts	100	100	100	100
symbols.ts	100	100	100	100
src/util	100	66.66	100	100
camelize.ts	100	100	100	100
warn.ts	100	50	100	100	7
src/vue	97.94	76.19	100	97.94
component.ts	100	100	100	100
directive.ts	96.8	64.28	100	96.8	52-55

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[Demivan]

@antfu @patak-dev Can you check this out?
This feels like much cleaner way of collecting coverage. I just don't know why coverage lines are reported incorrectly.

[antfu]

Let's give it a try!

[Demivan]

@antfu Coverage of fluent-vue did not change fluent-vue/fluent-vue#749 (comment) - that is good, and #378 is fixed.

Only downside is that you now get messages in console when running coverage:

Debugger listening on ws://127.0.0.1:44445/34776132-750c-4d57-ab2c-21b6f6f3172d
For help, see: https://nodejs.org/en/docs/inspector

Will check if I can disable this output.

[Demivan]

Will check if I can disable this output.

Cannot disable this message, NodeJs will always print it.