Make classes in ol/ available as named exports from ol

src/ol/structs/LRUCache.js

@@ -1,7 +1,7 @@
 /**
  * @module ol/structs/LRUCache
  */
-import {inherits} from '../index.js';
+import {inherits} from '../util.js';
 import {assert} from '../asserts.js';
 import EventTarget from '../events/EventTarget.js';
 import EventType from '../events/EventType.js';

src/ol/structs/RBush.js

@@ -1,7 +1,7 @@
 /**
  * @module ol/structs/RBush
  */
-import {getUid} from '../index.js';
+import {getUid} from '../util.js';
 import rbush from 'rbush';
 import {createOrUpdate, equals} from '../extent.js';
 import {isEmpty} from '../obj.js';