AutoTest: Refactor TestResult

* use enum class
* remove superfluous enum value
* remove superfluous subclass
* remove superfluous constructors
* simplify handling

Change-Id: Iecf11e62eb842c9d455d9238939244496f6b66f4
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/autotest/testrunner.h

@@ -86,6 +86,7 @@ private:
     void runTests();
     void debugTests();
     void runOrDebugTests();
+    void reportResult(ResultType type, const QString &description);
     explicit TestRunner(QObject *parent = nullptr);
 
     QFutureWatcher<TestResultPtr> m_futureWatcher;