Python: filter jump steps

Author: yoff

python/ql/lib/semmle/python/dataflow/new/internal/DataFlowPrivate.qll

@@ -301,7 +301,9 @@ module LocalFlow {
     or
     // General definition
     // TODO: remove other cases that are now redundant
-    nodeFrom.(CfgNode).getNode() = nodeTo.(CfgNode).getNode().(DefinitionNode).getValue()
+    nodeFrom.(CfgNode).getNode() = nodeTo.(CfgNode).getNode().(DefinitionNode).getValue() and
+    // remove jump steps (such as assignment of parameter default values)
+    nodeFrom.getEnclosingCallable() = nodeTo.getEnclosingCallable()
     or
     // With definition
     //   `with f(42) as x:`