FIx missing import

Author: Christoph Läubrich

platform-tests/src/test/java/org/junit/platform/reporting/open/xml/OpenTestReportGeneratingListenerTests.java

@@ -30,6 +30,7 @@
 import java.io.BufferedReader;
 import java.io.InputStreamReader;
 import java.io.PrintStream;
+import java.net.InetAddress;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.net.URISyntaxException;