Merge pull request #15238 from andrey-golubev:fluid_fix_journal

G-API: Fix Journal usage in Fluid backend (#15238)

* Fix Journal usage in Fluid backend

* Delete dumpDotRequired(): invalid check

* Update mem consumption test

* Test that new test works

* Debug memory consumption function

* Increase iterations in test

* Re-write memory consumption measurement part

* Restore correct fix for Fluid journals

modules/gapi/src/compiler/gmodel.cpp

@@ -185,6 +185,16 @@ void GModel::log(Graph &g, ade::EdgeHandle eh, std::string &&msg, ade::NodeHandl
     }
 }
 
+void GModel::log_clear(Graph &g, ade::NodeHandle node)
+{
+    if (g.metadata(node).contains<Journal>())
+    {
+        // according to documentation, clear() doesn't deallocate (__capacity__ of vector preserved)
+        g.metadata(node).get<Journal>().messages.clear();
+    }
+}
+
+
 ade::NodeHandle GModel::detail::dataNodeOf(const ConstLayoutGraph &g, const GOrigin &origin)
 {
     // FIXME: Does it still work with graph transformations, e.g. redirectWriter()??