MP OpenAPI: Add test for validation message output

We were testing for each of the problem messages we expect, but we
weren't testing for the top message which says "The following errors
were found:"

dev/com.ibm.ws.microprofile.openapi_fat/fat/src/com/ibm/ws/microprofile/openapi/validation/fat/OpenAPIValidationTestOne.java

@@ -79,6 +79,8 @@ public static void setUpTest() throws Exception {
         assertNotNull("The application openapi_validation was processed and an OpenAPI document was produced.",
             server.waitForStringInLog("CWWKO1660I.*and an OpenAPI document was produced.")); // wait for application to
                                                                                              // be processed
+        assertThat("Validation errors were reported", server.findStringsInLogs("CWWKO1650E"), not(empty()));
+        assertThat("Validation warnings were reported", server.findStringsInLogs("CWWKO1651W"), not(empty()));
         String openApiDoc = new HttpRequest(server, "/openapi").run(String.class);
         Log.info(OpenAPIValidationTestOne.class, "setUpTest", "OpenAPI doc:\n" + openApiDoc);
     }