[C++] Make JoynrTestGenerated a shared library.
[C++] Make JoynrTestGenerated a shared library.

To simplify ABI checker job, the JoynrTestGenerated is converted to
a SHARED library so that ABI changes on generated code can be directly
tested with it.

Change-Id: If8837b943bfed5aca35a63badc86a5e45af8eb27

clive-jevons/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,bmwcarit/joynr,clive-jevons/joynr,bmwcarit/joynr,bmwcarit/joynr,clive-jevons/joynr,bmwcarit/joynr,bmwcarit/joynr,clive-jevons/joynr,clive-jevons/joynr,clive-jevons/joynr