testsuite/integration/elytron uses directly a jboss.dist dir when set instead of its copy in the target dir

When the jboss.dist property is set for the mvn command, the testsuite/integration/elytron project uses directly a server distribution in the jboss.dist directory instead of its copy in the target/wildfly directory, and the distribution is customized with the modify-elytron-config.cli script.

As a result, when running the test suite in the elytron mode (-Delytron), the next testing module (compat) fails.

It also brings difficulties when developing tests in the elytron test module itself.