Resource folder path resolution from classloader

[poslegm]

I think it's more reliable way to get resources. Should fix issue #1681 (comment)

[kitbellew]

i checked it out and ran. unlike before, intellij ran tests. however, i am not sure if this behaviour is as before, as it stopped after 1270 tests, while there are supposed to be 3810 of them.

so while this change is good, perhaps @olafurpg is right and we should take another look at munit integration with scalafmt.

[poslegm]

It's correct behaviour, because there is 1270 format tests. IDEA renders it wrong: scalameta/munit#47

Ok, we can revert MUnit migration if it interferes with work on scalafmt. IDEA issues looks confusing.

[kitbellew]

@poslegm if the issue is simply that intellij renders it wrong, i don't care. just wanted to be sure it runs all tests, so that my continued messing with the codebase doesn't introduce bugs accidentally. :)

[olafurpg]

I don’t want the MUnit migration to regress the experience of testing via IntelliJ so please feel free to revert back to ScalaTest. Since MUnit is just a JUnit runner I think the IntelliJ testing UX can be amazingly good but it’s not there yet.