Use set/get on AtomicBoolean compatibility with Java 8

Author: marcphilipp

junit-platform-commons/src/main/java/org/junit/platform/commons/util/ReflectionUtils.java

@@ -1261,8 +1261,8 @@ public static boolean isNestedClassPresent(Class<?> clazz, Predicate<Class<?>> p
 Preconditions.notNull(predicate, "Predicate must not be null");
 
 AtomicBoolean foundNestedClass = new AtomicBoolean(false);
-visitAllNestedClasses(clazz, predicate, __ -> foundNestedClass.setPlain(true));
-return foundNestedClass.getPlain();
+visitAllNestedClasses(clazz, predicate, __ -> foundNestedClass.set(true));
+return foundNestedClass.get();
 }
 
 /**