(7.0.z) Clean-up test deployment dependencies

In the cxf-specific testsuite, we have some test deployments specifying dependencies to module org.apache.cxf.impl, which is private and should hence not be used unless there's a real reason for doing that.
With the upgrade to Apache CXF 3 series, the org.apache.cxf module now contains cxf-rt-core.jar instead of cxf-api.jar, so the public org.apache.cxf module can be used instead of the org.apache.cxf.impl one in some scenarios (where cxf core classes usage where the reason for setting the dependency).