from JDK-8225624:
after reading the code (and trying not to cry blood), I realized that all these vmTestbase/jit/graph/cgt* can hide failures: CGT creates a number of CGTThread which do actual testing and verification; in case something goes wrong, CGTThread throws an exception; and b/c we run thru ExecDriver there is no jtreg UncaughtExceptionHandler to threat all uncaught exception as test failures. I'm going to rework these tests so we won't need ExecDriver to run them and to make them a tiny bit more pleasant to read.