Switch LogReader::Nodes to LoggedNodes

If folks want a list of nodes from the simulated config, they should
instead use the factory configuration.  Most of the time, we want to
instead use the nodes from the logged configuration.  Flip everything
over.

We should probably consider removing the helper since it doesn't really
add much.

Change-Id: I8f2150df9c50acfc0d7444f42b37820516fe072f
diff --git a/aos/events/logging/logger.cc b/aos/events/logging/logger.cc
index d5eeff4..8253220 100644
--- a/aos/events/logging/logger.cc
+++ b/aos/events/logging/logger.cc
@@ -1067,16 +1067,8 @@
   return remapped_configuration_;
 }
 
-std::vector<const Node *> LogReader::Nodes() const {
-  // Because the Node pointer will only be valid if it actually points to
-  // memory owned by remapped_configuration_, we need to wait for the
-  // remapped_configuration_ to be populated before accessing it.
-  //
-  // Also, note, that when ever a map is changed, the nodes in here are
-  // invalidated.
-  CHECK(remapped_configuration_ != nullptr)
-      << ": Need to call Register before the node() pointer will be valid.";
-  return configuration::GetNodes(remapped_configuration_);
+std::vector<const Node *> LogReader::LoggedNodes() const {
+  return configuration::GetNodes(logged_configuration());
 }
 
 monotonic_clock::time_point LogReader::monotonic_start_time(