ISPN-4938 Infinispan Commons Util package is not in generated Javadoc

* Also fixed import in interface
ISPN-4886 SingleNodeJdbcStoreIT.testForcedShutdown and
testNormalShutdown random failures

* Made sure we put the same byte as the test consistently
JavaDoc: multiline code examples are mangled
Revert "Revert rebalancing per cache"

This reverts commit 8cbba22ae625c7dd3e8f5ff389b71f4b49aec2b4.