Refine null-safety in the spring-core module

See gh-34150

spring-core/src/main/java/org/springframework/util/Assert.java

@@ -319,7 +319,7 @@ public static void doesNotContain(@Nullable String textToSearch, String substrin
 	 * @throws IllegalArgumentException if the object array is {@code null} or contains no elements
 	 */
 	@Contract("null, _ -> fail")
-	public static void notEmpty(Object @Nullable [] array, String message) {
+	public static void notEmpty(@Nullable Object @Nullable [] array, String message) {
 		if (ObjectUtils.isEmpty(array)) {
 			throw new IllegalArgumentException(message);
 		}