Convert EE Concurrency tests in testsuite/integration/basic to jar packaging

A number tests in the org.jboss.as.test.integration.ee.concurrent package package the test deployment as a war, even though the test is actually purely in-container invocation of a local ejb or an injected EE Concurrency object. This complicates use of these tests of Galleon layers, as it requires the provisioned server to include layers to provide support for wars. That's not a huge problem but ideally for layers testing we want to run tests against servers with the minimal set of layers truly needed.