AutoTest: Create tree item for each failure

Introduce special location item for this purpose.

Task-number: QTCREATORBUG-20967
Change-Id: Icb6c6ec8ff9d2e4e8e3d13834427bae50d74bd2a
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/autotest/testresult.cpp

@@ -136,6 +136,8 @@ QString TestResult::resultToString(const Result::Type type)
         return QString("BPASS");
     case Result::BlacklistedFail:
         return QString("BFAIL");
+    case Result::MessageLocation:
+        return QString();
     default:
         if (type >= Result::INTERNAL_MESSAGES_BEGIN && type <= Result::INTERNAL_MESSAGES_END)
             return QString();