AutoTest: Add option to disable derived checks

Previously the quick test parser would always check each symbol
its interested in to see if it might be derived from "TestCase".
This is very expensive.

This patch adds an option allowing the user to
enable or disable the check.

By default the check is disabled.

Change-Id: Ia6b230b344add672e53ad7fb52845c78a2914b99
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/autotest/quick/quicktestparser.h

@@ -33,7 +33,8 @@ public:
 
 private:
     bool handleQtQuickTest(QFutureInterface<TestParseResultPtr> &futureInterface,
-                           CPlusPlus::Document::Ptr document, ITestFramework *framework);
+                           CPlusPlus::Document::Ptr document,
+                           ITestFramework *framework);
     void handleDirectoryChanged(const QString &directory);
     void doUpdateWatchPaths(const QStringList &directories);
     QString quickTestName(const CPlusPlus::Document::Ptr &doc) const;
@@ -43,6 +44,7 @@ private:
     QFileSystemWatcher m_directoryWatcher;
     QMap<QString, QMap<QString, QDateTime> > m_watchedFiles;
     QMap<Utils::FilePath, Utils::FilePath> m_mainCppFiles;
+    bool m_checkForDerivedTests = false;
 };
 
 } // namespace Internal