Have some across several ebuilds that devs know fail during emerges, when tests are enabled. One example at least is
Can we engineer a method to disable these tests to avoid spurious bugs? This would be especially useful where
devs had no plans to fix in certain versions, especially system ebuilds
applied to individual tests? is this even possible/trivial to do?
Not portage. You need to file bugs about the broken ebuilds, so that RESTRICT="test" can be put there if there's no better solution.