[C++] Added WildcardStorageTest for inserting keys sharing same prefix
[C++] Added WildcardStorageTest for inserting keys sharing same prefix

* Multiple keys are used which share the same prefix so that
  RadixTree is forced to generate a common internal node
  with that prefix

* Multiple values are inserted for the same key. This works correctly
  only if WildcardStorage::insert() is able to detect that a node
  for exactly the same key exists already when insertion of
  additional values per key. In order to do so, it must compare
  the fullKey of the node, instead of the (partial) key which does
  not contain the common prefix.

Change-Id: I051c8f81567b612572b7cd0f6641e435377c1b21

bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr