Removes java.net.preferIPv4Stack hack

spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/config/GatewayConfiguration.java

@@ -25,6 +25,7 @@ import org.springframework.context.annotation.Configuration;
  */
 @Configuration
 public class GatewayConfiguration {
+
 	@Bean
 	public Marker gatewayMarker() {
 		return new Marker();

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/test/BaseWebClientTests.java

@@ -43,11 +43,6 @@ public class BaseWebClientTests {
 	protected static final String ROUTE_ID_HEADER = "X-Gateway-Route-Id";
 	protected static final Duration DURATION = Duration.ofSeconds(5);
 
-	static {
-		//TODO: wait for option in boot 2.0
-		System.setProperty("java.net.preferIPv4Stack", "true");
-	}
-
 	@LocalServerPort
 	protected int port = 0;
 

spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/test/GatewayTestApplication.java

@@ -90,7 +90,6 @@ public class GatewayTestApplication {
 	}
 
 	public static void main(String[] args) {
-		System.setProperty("java.net.preferIPv4Stack", "true"); //Remove when configurable
 		SpringApplication.run(GatewayTestApplication.class, args);
 	}
 }

spring-cloud-gateway-sample/src/main/java/org/springframework/cloud/gateway/sample/GatewaySampleApplication.java

@@ -53,7 +53,6 @@ public class GatewaySampleApplication {
 	}
 
 	public static void main(String[] args) {
-		System.setProperty("java.net.preferIPv4Stack", "true"); //Remove when configurable
 		SpringApplication.run(GatewaySampleApplication.class, args);
 	}
 }

spring-cloud-gateway-sample/src/test/java/org/springframework/cloud/gateway/sample/GatewaySampleApplicationTests.java

@@ -41,10 +41,6 @@ import static org.springframework.boot.test.context.SpringBootTest.WebEnvironmen
 @RunWith(SpringRunner.class)
 @SpringBootTest(classes = GatewaySampleApplication.class, webEnvironment = RANDOM_PORT)
 public class GatewaySampleApplicationTests {
-	static {
-		//TODO: wait for option in boot 2.0
-		System.setProperty("java.net.preferIPv4Stack", "true");
-	}
 
 	@LocalServerPort
 	protected int port = 0;