Remove the second parameter of substring() if possible

Closes gh-5720

spring-boot/src/test/java/org/springframework/boot/context/config/ConfigFileApplicationListenerTests.java

@@ -464,7 +464,7 @@ public class ConfigFileApplicationListenerTests {
 			assertThat(index)
 					.as("Loading profile '" + profile + "' not found in '" + log + "'")
 					.isNotEqualTo(-1);
-			log = log.substring(index + line.length(), log.length());
+			log = log.substring(index + line.length());
 		}
 	}