Utils: Reserve a container before you use transform

It is seen as good practice to use Container::reserve if you know the size
in advance.

Change-Id: If1398eaa099f4d3f657778aca46516f9bdec14c9
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/libs/utils/algorithm.h

@@ -240,6 +240,7 @@ struct TransformImpl {
     static C call(const SC &container, F function)
     {
         C result;
+        result.reserve(container.size());
         std::transform(container.begin(), container.end(),
                        inserter(result),
                        function);