Fix HttpHeaders.setHost() to remove the header

See gh-33716

spring-web/src/main/java/org/springframework/http/HttpHeaders.java

@@ -1136,7 +1136,7 @@ public class HttpHeaders implements MultiValueMap<String, String>, Serializable
 			set(HOST, value);
 		}
 		else {
-			remove(HOST, null);
+			remove(HOST);
 		}
 	}