Fix NodeSecurityContextPropagationTest

Author: shishkovilja

modules/core/src/test/java/org/apache/ignite/internal/processors/security/NodeSecurityContextPropagationTest.java

@@ -53,7 +53,6 @@
 import static org.apache.ignite.events.EventType.EVT_NODE_LEFT;
 import static org.apache.ignite.internal.IgniteNodeAttributes.ATTR_IGNITE_INSTANCE_NAME;
 import static org.apache.ignite.internal.events.DiscoveryCustomEvent.EVT_DISCOVERY_CUSTOM_EVT;
-import static org.apache.ignite.testframework.GridTestUtils.getFieldValue;
 import static org.apache.ignite.testframework.GridTestUtils.runAsync;
 import static org.apache.ignite.testframework.GridTestUtils.waitForCondition;
 
@@ -185,7 +184,7 @@ private boolean anyReceivedMessageMatch(IgniteEx ignite, Predicate<Object> predi
             Object unwrappedMsg = msg;
 
             if (msg instanceof TcpDiscoveryCustomEventMessage) {
-                DiscoverySpiCustomMessage customMsg = getFieldValue(msg, "serMsg");
+                DiscoverySpiCustomMessage customMsg = ((TcpDiscoveryCustomEventMessage)msg).message();
 
                 assert customMsg instanceof SecurityAwareCustomMessageWrapper;