in some cases, not all extra @requires properties can't be set. one of common example is an inability to set vm properties due to the mismatch b/w test suite (namely sun/hotspot/whitebox class) and JDK. currently, we can either fail before running any tests or set a default value (usually 'null') to the property. the former is too strict, as it affects even runs which don't depend on a value of "buggy" properties, the later might lead to incorrect test selection.

if jtreg provides a way for requires.extraPropDefns classes to explicitly indicate such situation, it will be able to detect all tests which use such properties and use error status for these tests.