JCache improved concurrency of CacheManager and CacheProvider impls

CacheManager and CacheProvider removed sync
CacheRecordStore improved checkstyle
CacheStatistics added to ICache and impl for server mode
I'm not familiar with the surroundings of the usage of this code, but if it can happen that 2 threads at the same time execute this method, than there is a potential data-race here. There is a non atomic check/modify which can lead to multiple HazelcastInstances being created.