public static int findAvailableTcpPort() {
        return findAvailableTcpPort(PORT_RANGE_MIN);
    }
Find an available TCP port randomly selected from the range
[{@value #PORT_RANGE_MIN}, {@value #PORT_RANGE_MAX}].
@return an available TCP port number
@throws IllegalStateException if no available port could be found
agent-module/plugins-test-module/testcase/src/main/java/com/navercorp/pinpoint/testcase/util/SocketUtils.java