feat(test): Use dynamic port allocation in integration tests (#133)

- Add TestUtil class with findAvailablePort() method to the mcp-test module
- Add findAvailablePort() method to TomcatTestUtil classes
- Replace hardcoded port numbers with dynamic port allocation

Signed-off-by: Christian Tzolov <christian.tzolov@broadcom.com>

mcp-test/src/main/java/io/modelcontextprotocol/server/TestUtil.java

@@ -0,0 +1,31 @@
+/*
+* Copyright 2025 - 2025 the original author or authors.
+*/
+package io.modelcontextprotocol.server;
+
+import java.io.IOException;
+import java.net.InetSocketAddress;
+import java.net.ServerSocket;
+
+public class TestUtil {
+
+	TestUtil() {
+		// Prevent instantiation
+	}
+
+	/**
+	 * Finds an available port on the local machine.
+	 * @return an available port number
+	 * @throws IllegalStateException if no available port can be found
+	 */
+	public static int findAvailablePort() {
+		try (final ServerSocket socket = new ServerSocket()) {
+			socket.bind(new InetSocketAddress(0));
+			return socket.getLocalPort();
+		}
+		catch (final IOException e) {
+			throw new IllegalStateException("Cannot bind to an available port!", e);
+		}
+	}
+
+}