ISPN-2264 and ISPN-3419

ISPN-2264 DistL1WriteSkewTest.testSharedCounter failing randomly
* re-enabled testSharedCounter
* update the test code by removing the assert keyword

ISPN-3419 Write Skew check must be performed only in the primary owner
* the write skew check is only performed in the primary owner. In Replicated mode, this was already done so I only changed for the distribution mode.


https://issues.jboss.org/browse/ISPN-2264
https://issues.jboss.org/browse/ISPN-3419