CA: integrate BasicSnapshotStore with drasnapshot.Snapshot

Store the DRA snapshot inside the current internal data in
SetClusterState().

Retrieve the DRA snapshot from the current internal data in
DraSnapshot().

Clone the DRA snapshot whenever the internal data is cloned
during Fork(). This matches the forking logic that BasicSnapshotStore
uses, ensuring that the DRA object state is correctly
forked/commited/reverted during the corresponding ClusterSnapshot
operations.

This should be a no-op, as DraSnapshot() isn't called anywhere yet,
adn no DRA snapshot is passed to SetClusterState() yet.

cluster-autoscaler/simulator/clustersnapshot/store/basic.go

@@ -36,6 +36,7 @@ type BasicSnapshotStore struct {
 type internalBasicSnapshotData struct {
 	nodeInfoMap        map[string]*schedulerframework.NodeInfo
 	pvcNamespacePodMap map[string]map[string]bool
+	draSnapshot        drasnapshot.Snapshot
 }
 
 func (data *internalBasicSnapshotData) listNodeInfos() []*schedulerframework.NodeInfo {
@@ -142,6 +143,7 @@ func (data *internalBasicSnapshotData) clone() *internalBasicSnapshotData {
 	return &internalBasicSnapshotData{
 		nodeInfoMap:        clonedNodeInfoMap,
 		pvcNamespacePodMap: clonedPvcNamespaceNodeMap,
+		draSnapshot:        data.draSnapshot.Clone(),
 	}
 }
 
@@ -208,8 +210,7 @@ func (snapshot *BasicSnapshotStore) getInternalData() *internalBasicSnapshotData
 
 // DraSnapshot returns the DRA snapshot.
 func (snapshot *BasicSnapshotStore) DraSnapshot() drasnapshot.Snapshot {
-	// TODO(DRA): Return DRA snapshot.
-	return drasnapshot.Snapshot{}
+	return snapshot.getInternalData().draSnapshot
 }
 
 // GetNodeInfo gets a NodeInfo.
@@ -262,7 +263,7 @@ func (snapshot *BasicSnapshotStore) SetClusterState(nodes []*apiv1.Node, schedul
 			}
 		}
 	}
-	// TODO(DRA): Save DRA snapshot.
+	snapshot.getInternalData().draSnapshot = draSnapshot
 	return nil
 }