Let Maven decide the appropriate amount of concurrency

Jenkinsfile

@@ -38,7 +38,7 @@ timestampedNode('java') {
                 // The -Dmaven.repo.local=${pwd()}/.repository means that Maven will create a
                 // .repository directory at the root of the build (which it gets from the
                 // pwd() Workflow call) and use that for the local Maven repository.
-                sh "mvn -Pdebug -U clean install ${runTests ? '-Dmaven.test.failure.ignore=true -Dconcurrency=1' : '-DskipTests'} -V -B -Dmaven.repo.local=${pwd()}/.repository"
+                sh "mvn -Pdebug -U clean install ${runTests ? '-Dmaven.test.failure.ignore=true' : '-DskipTests'} -V -B -Dmaven.repo.local=${pwd()}/.repository"
             }
         }
     }