move isClearingPhetioDynamicElementsProperty to tandem/, phetsims/tan…

…dem#294

Signed-off-by: Michael Kauzmann <[email protected]>

js/Sim.ts

@@ -195,11 +195,6 @@ export default class Sim extends PhetioObject {
   // If any sim screen has keyboard help content, trigger creation of a keyboard help button.
   public readonly hasKeyboardHelpContent: boolean;
 
-  // if PhET-iO is currently setting the state of the simulation and in the process of clearing dynamic elements as a
-  // precursor to setting the state of those elements. See PhetioStateEngine for details. This must be
-  // declared before soundManager.initialized is called.
-  public readonly isClearingPhetioDynamicElementsProperty: TReadOnlyProperty<boolean>;
-
   // (joist-internal)
   public readonly version: string = packageJSON.version;
 
@@ -594,10 +589,6 @@ export default class Sim extends PhetioObject {
     assert && assert( !window.phet.joist.sim, 'Only supports one sim at a time' );
     window.phet.joist.sim = this;
 
-    this.isClearingPhetioDynamicElementsProperty = Tandem.PHET_IO_ENABLED ?
-                                                   phet.phetio.phetioEngine.phetioStateEngine.isClearingDynamicElementsProperty :
-                                                   new BooleanProperty( false );
-
     // commented out because https://github.com/phetsims/joist/issues/553 is deferred for after GQIO-oneone
     // if ( PHET_IO_ENABLED ) {
     //   this.engagementMetrics = new EngagementMetrics( this );