more and more tests in hotspot test suite starts to depend on shared classes (e.g. WhiteBox library in /test/lib/, common testlibrary in /test/lib/shared/classes, test-library specific for tests, etc). In some cases, such tests fail due to class not found errors at both compile and run time. Those failure are stochastic and hence hard to reproduce, investigate, fix. For the time being, it's unclear if it's an issue w/ tests, test libraries or test harnesses.
Hence we need to improve our tools to handle such situation in more deterministic way (make all non-zero probabilities of failure equal to 1), and to identify all such issues.