VFP test take 2: make Disposer disposing faster

platform/platform-tests/testSrc/com/intellij/openapi/vfs/impl/VirtualFilePointerTest.java

@@ -398,11 +398,11 @@ public class VirtualFilePointerTest extends PlatformLangTestCase {
     PlatformTestUtil.startPerformanceTest("VF container create/delete",200, new ThrowableRunnable() {
       @Override
       public void run() throws Exception {
+        Disposable parent = Disposer.newDisposable();
         for (int i = 0; i < 10000; i++) {
-          Disposable parent = Disposer.newDisposable();
           myVirtualFilePointerManager.createContainer(parent);
-          Disposer.dispose(parent);
         }
+        Disposer.dispose(parent);
       }
     }).cpuBound().assertTiming();
   }

platform/util/src/com/intellij/openapi/util/objectTree/ObjectNode.java

@@ -26,6 +26,7 @@ import org.jetbrains.annotations.TestOnly;
 
 import java.util.Collection;
 import java.util.Collections;
+import java.util.ListIterator;
 
 public final class ObjectNode<T> {
   private static final ObjectNode[] EMPTY_ARRAY = new ObjectNode[0];
@@ -73,7 +74,13 @@ public final class ObjectNode<T> {
   void removeChild(@NotNull ObjectNode<T> child) {
     synchronized (myTree.treeLock) {
       assert myChildren != null: "No children to remove child: " + this + ' ' + child;
-      myChildren.remove(child);
+      ListIterator<ObjectNode<T>> iterator = myChildren.listIterator(myChildren.size());
+      while (iterator.hasPrevious()) {
+        if (child.equals(iterator.previous())) {
+          iterator.remove();
+          return;
+        }
+      }
     }
   }