QA's building scripts need to be simplified

build-jta.xml, build-jts.xml, buid-core.xml and build.xml are ant scripts that make up the building system of the QA test suite. The interaction between these scripts results in compiling a specific set of files needed to run a set of tests in run-tests.xml.

At the moment, only build-jts.xml works. The other two scripts (i.e. build-jta.xml and buid-core.xml) don't execute correctly and, as a consequence, they cannot be used. As build-jts.xml is also the superset of build-jta.xml and buid-core.xml, it makes sense to modify QA's building system to only use build-jts.xml.

NOTE: in build-jt*.xml scripts there is an ant target to compile integration tests that should run on EAP/WFLY. As the dependencies/jar files used to compile integration tests are out of date, it's very likely that that ant target won't work. As part of this JIRA, it's useful to double check the correctness of this script. In case it does not work, a new Jira should be created to move those tests somewhere else (within the Narayana code base or, for example, directly in WFLY). IMPORTANT: please, report the commit hash in the Jira that tracks the migration of astests