(squash) Make another 2 suggested changes

Make save reset variables to original variables defined in schema, and
put coverage off/on around unimplemented methods.

DataProcessor.scala: Ensure variableMap is serialized as well as
validationMode, but reset back to original variables when saving.

Runtime2DataProcessor.scala: Put coverage off/on around unimplemented
methods.

daffodil-runtime1/src/main/scala/org/apache/daffodil/processors/DataProcessor.scala

@@ -88,19 +88,19 @@ object DataProcessor {
    * It enables us to implement restrictions on what you can/cannot do with a reloaded
    * processor versus an original one.
    *
-   * When we reload a processor, it will have default values for everything settable
+   * When we reload a processor, we want it to have default values for everything settable
    * like validation mode, debug mode, and debugger.
    *
-   * Note that this class does preserve validationMode. That is because validationMode
-   * may be needed by serializations other than our own save/reload (e.g., Apache Spark
+   * Note that this class does preserve variableMap and validationMode. That is because
+   * serializations other than our own save/reload may need such settings (e.g., Apache Spark
    * which serializes to move objects for remote execution).
    *
-   * Hence, we're depending on the save method to explicitly turn off validationMode.
+   * Hence, we're depending on the save method to explicitly reset them to default values.
    */
   private class SerializableDataProcessor(
     ssrd: SchemaSetRuntimeData,
     tunables: DaffodilTunables,
-    variableMap: VariableMap,
+    variableMap: VariableMap,            // must be explicitly reset by save method
     validationMode: ValidationMode.Type, // must be explicitly turned off by save method
   ) extends DataProcessor(ssrd, tunables, variableMap, validationMode) {
 
@@ -270,13 +270,14 @@ class DataProcessor(
 
     //
     // Make a copy of this object so that we can make its saved state
-    // different than its original state.  Note that the serialization
-    // system *does* preserve validationMode since it may be required by
-    // other software like Apache Spark. But for our save/reload purposes,
-    // we don't want validationMode preserved.
+    // different than its original state.  Note other software like
+    // Apache Spark may require variableMap and validationMode to be
+    // preserved.  But for our save/reload purposes, we want to reset
+    // them back to their original values.
     //
     val dpToSave = this.copy(
-      validationMode = ValidationMode.Off, // explicitly turn off, so restored processor won't be validating.
+      variableMap = ssrd.originalVariables, // reset to original variables defined in schema
+      validationMode = ValidationMode.Off,  // explicitly turn off, so restored processor won't be validating
     )
 
     try {

daffodil-runtime2/src/main/scala/org/apache/daffodil/runtime2/Runtime2DataProcessor.scala

@@ -39,12 +39,12 @@ import org.apache.daffodil.util.Maybe
 import org.apache.daffodil.util.Maybe.Nope
 
 /**
- * Effectively a scala proxy object that does its work via the underlying C-code.
- * Will need to consider how to use features of underlying C-code to get infoset,
- * walk infoset, generate XML for use by TDML tests.
+ * Effectively a scala proxy object that does its work via the underlying C-code
+ * to get infoset, walk infoset, and generate XML for use by TDML tests.
  */
 class Runtime2DataProcessor(executableFile: os.Path) extends DFDL.DataProcessorBase {
 
+  //$COVERAGE-OFF$
   override def withValidationMode(mode: ValidationMode.Type): DFDL.DataProcessor = ???
   override def withTunable(name: String, value: String): DFDL.DataProcessor = ???
   override def withTunables(tunables: Map[String, String]): DFDL.DataProcessor = ???
@@ -53,12 +53,11 @@ class Runtime2DataProcessor(executableFile: os.Path) extends DFDL.DataProcessorB
   override def withExternalVariables(extVars: Seq[Binding]): DFDL.DataProcessor = ???
   override def withDebugger(dbg:AnyRef): DFDL.DataProcessor = ???
   override def withDebugging(flag: Boolean): DFDL.DataProcessor = ???
-
   override def save(output: DFDL.Output): Unit = ???
-
   override def tunables: DaffodilTunables = ???
   override def variableMap: VariableMap = ???
   override def validationMode: ValidationMode.Type = ???
+  //$COVERAGE-ON$
 
   /**
    * Returns an object which contains the result, and/or diagnostic information.