Added test case for detector to find methods of return type Boolean that may return null.
Added test case for detector to find methods of return type Boolean that may return null.

git-svn-id: e7d6bde23f017c9ff4efd468d79d66def666766b@9137 eae3c2d3-9b19-0410-a86e-396b6ccb6ab3

KengoTODA/spotbugs,sewe/spotbugs,johnscancella/spotbugs,sewe/spotbugs,johnscancella/spotbugs,spotbugs/spotbugs,spotbugs/spotbugs,KengoTODA/spotbugs,sewe/spotbugs,sewe/spotbugs,KengoTODA/spotbugs,johnscancella/spotbugs,KengoTODA/spotbugs,spotbugs/spotbugs,spotbugs/spotbugs,spotbugs/spotbugs,johnscancella/spotbugs