[RefactoredBMS] Add log before doRestoreFinished is called on BackupAgent.

This CL replicates ag/2140301 in RefactoredBMS.

Test: runtest -p com.android.server.backup frameworks-services
Bug: 37973765
Change-Id: I2c2795c89035dd6c38aee8aec4e4a95cfdba0846

services/backup/java/com/android/server/backup/restore/PerformUnifiedRestoreTask.java

@@ -779,6 +779,9 @@ public class PerformUnifiedRestoreTask implements BackupRestoreTask {
 
     // state RESTORE_FINISHED : provide the "no more data" signpost callback at the end
     private void restoreFinished() {
+        if (DEBUG) {
+            Slog.d(TAG, "restoreFinished packageName=" + mCurrentPackage.packageName);
+        }
         try {
             backupManagerService
                     .prepareOperationTimeout(mEphemeralOpToken,