Don't discard all information about passing tests immidately

[oxinabox]

Right now the testing infrastructure itself discards all information for passing tests.
The Pass result type has fields for all the information, and a show method that would display it, but they are all blanked out with nothing etc as their values.

julia/stdlib/Test/src/Test.jl

Line 432 in 6a45619

value ? Pass(:test, nothing, nothing, value) :

Determining whether or not to do this should not be done there.
It should be done in the record method of the testset.
That way it can be configured.

record(::DefaultTestSet, ::Pass) already discards the pass result entirely anyway.

I don't even think doing it later will cost memory, all that information is being captured anyway so that it can be reported for Failure/

[ararslan]

I believe the fact that information about passing tests is discarded is actually deliberate. I'm having a difficult time finding a discussion here on GitHub, but I recall that there was an issue with the amount of memory that large test sets were racking up since they were retaining too much information. I thought the resolution to that was to discard information about passes, but I could be misremembering this entirely.

[oxinabox]

I think that is covered by discarding the whole Pass result

julia/stdlib/Test/src/Test.jl

Lines 663 to 666 in 6a45619

	# For a broken result, simply store the result
	record(ts::DefaultTestSet, t::Broken) = (push!(ts.results, t); t)
	# For a passed result, do not store the result since it uses a lot of memory
	record(ts::DefaultTestSet, t::Pass) = (ts.n_passed += 1; t)

It doesn't need to be empty when discarded -- it is being constructed (with nothings) then discarded.
It might as well be constructed filled,
and then TestSets can override the behavior of what to do with it. Default can still discard it, and other TestSets can instead add it to results.

[KristofferC]

I believe the fact that information about passing tests is discarded is actually deliberate. I'm having a difficult time finding a discussion here on GitHub, but I recall that there was an issue with the amount of memory that large test sets were racking up since they were retaining too much information. I thought the resolution to that was to discard information about passes, but I could be misremembering this entirely.

#20150

[oxinabox]

So the PR that introduced this discarding of the fields of Pass was
#18738
(One of many things it did)

@kshyatt am I right in saying this was an earlier attempt at decreasing memory use,
and with the changes from #20150 that it can be undone, so we just discard pass wholely.

[mmiller-max]

Just bumping this, as retaining the pass information will help greatly in the writing of test reports which we are doing in TestReports.jl.

I've got the changes ready for a PR here, but first it'd be good to have confirmation here that this will not have any negative performance impacts (because of the changes made in #20150).