DeadlockDetector in core has code never used by core

The DeadlockDetector class has some functionality needed by core but it also has some other utility methods (see main, loadGraphs, and loadGraph) that could be moved out of core since the product never uses them. loadGraph calls readObject which is flagged as a critical security issue by "JFrog Artifactory for the Jenkins Pipeline". Perhaps this internal diagnostic code could be moved into geode's test jar.