QmlDesigner: Do not clear component cache

We share the engine now with other views.

Change-Id: Icfb1b5bc11e3f2c05f7813ef487348478352f387
Reviewed-by: Henning Gründl <henning.gruendl@qt.io>

src/plugins/qmldesigner/components/stateseditornew/stateseditorwidget.cpp

@@ -163,7 +163,6 @@ void StatesEditorWidget::reloadQmlSource()
 {
     QString statesListQmlFilePath = qmlSourcesPath() + QStringLiteral("/Main.qml");
     QTC_ASSERT(QFileInfo::exists(statesListQmlFilePath), return );
-    engine()->clearComponentCache();
     setSource(QUrl::fromLocalFile(statesListQmlFilePath));
 
     if (!rootObject()) {