Autotest: Slim down TestFrameworkManager interface

- sort frameworks at insertion time
- apply the 'static' pattern
- inline code from convenience functions that are only used once on
  the caller side

Change-Id: Ic4a46ad9487c58b4dfd61658a6fccebb88a428a9
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/autotest/testnavigationwidget.cpp

@@ -76,7 +76,9 @@ TestNavigationWidget::TestNavigationWidget(QWidget *parent) :
     QHBoxLayout *hLayout = new QHBoxLayout;
     m_missingFrameworksWidget->setLayout(hLayout);
     hLayout->addWidget(new QLabel(tr("No active test frameworks.")));
-    m_missingFrameworksWidget->setVisible(!TestFrameworkManager::instance()->hasActiveFrameworks());
+    const bool hasActiveFrameworks = Utils::anyOf(TestFrameworkManager::registeredFrameworks(),
+                                                  &ITestFramework::active);
+    m_missingFrameworksWidget->setVisible(!hasActiveFrameworks);
     QVBoxLayout *layout = new QVBoxLayout;
     layout->setContentsMargins(0, 0, 0, 0);
     layout->setSpacing(0);