Python: explain the regression test

Author: yoff

python/ql/test/experimental/dataflow/regression/dataflow.ql

@@ -1,3 +1,10 @@
+/**
+ * This should be compared to
+ * python/ql/test/library-tests/taint/dataflow/Dataflow.ql
+ * A first goal is to have identical results; after that we
+ * hope to remove the false positive.
+ */
+
 import config
 
 from