mnk-5514, adding extra assert that might help

git-svn-id: http://svn.terracotta.org/svn/ehcache@8088 b9324663-ca0f-0410-8574-be9b3887307d
mnk-5514, merge 8088 in 2.5.x

git-svn-id: http://svn.terracotta.org/svn/ehcache@8089 b9324663-ca0f-0410-8574-be9b3887307d
mnk-5457, keep processing next dead bucket

git-svn-id: http://svn.terracotta.org/svn/ehcache@8090 b9324663-ca0f-0410-8574-be9b3887307d
mnk-5457, merge 8090 in 2.7.x

git-svn-id: http://svn.terracotta.org/svn/ehcache@8091 b9324663-ca0f-0410-8574-be9b3887307d
mnk-5457, merge 8090 in 2.8.x

git-svn-id: http://svn.terracotta.org/svn/ehcache@8092 b9324663-ca0f-0410-8574-be9b3887307d