Add test utility methods for checking the test environment that don't throw AssumptionViolationException but instead return a boolean

Not all use cases for the kind of test environment checking that AssumeTestGroupUtil does can handle having ATGU throw an AssumptionViolatedException. Sometimes that may be caught and ignored (e.g. in a ServerSetup); other times it won't be caught and will fail the test (e.g. in a static @Deployment method). For these cases, some form of conditional logic is needed; e.g. turn a ServerSetup method into a no-op or return an 'empty' deployment from the @Deployment method.

So for each 'assumeXXX' method that throws AssumptionViolatedException, there should be a corresponding 'isXXX' method that returns a boolean.

I did some of this downstream to support conditional behavior based on SE version but it seems I never applied it upstream.