Fix resource leak in PortAllocator canBind method

The canBind method in PortAllocator had a potential resource leak where
ServerSocket instances might not be properly closed if an exception
occurred between socket creation and the explicit close() call.

Fixed by using try-with-resources statement which ensures the
ServerSocket is automatically closed regardless of whether an
exception is thrown or not.

This prevents potential socket handle leaks in the testing framework.

Author: hoteye

testing-common/src/main/java/io/opentelemetry/instrumentation/test/utils/PortAllocator.java

@@ -118,9 +118,7 @@ Closeable bind(int port) {
     }
 
     boolean canBind(int port) {
-      try {
-        ServerSocket socket = new ServerSocket(port);
-        socket.close();
+      try (ServerSocket socket = new ServerSocket(port)) {
         return true;
       } catch (IOException exception) {
         return false;