Sqlite: Add exception if statement is called outside of a lock

Sometimes it is really hard to trace if sqlite statement is called
outside of a database connection lock. So we know throw an exception
in the unit test. So we get failing tests.

Change-Id: I71485b9473075751a2fb771ce7e2954e28d8413e
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/libs/sqlite/sqliteexception.h

@@ -410,4 +410,12 @@ public:
     {}
 };
 
+class DatabaseIsNotLocked : public Exception
+{
+public:
+    DatabaseIsNotLocked(const char *whatErrorHasHappen)
+        : Exception(whatErrorHasHappen)
+    {}
+};
+
 } // namespace Sqlite