Python: Fix remaining deprecation warnings.

Author: tausbn

python/ql/src/Resources/FileOpen.qll

@@ -79,7 +79,7 @@ predicate def_is_open(EssaDefinition def, ControlFlowNode open) {
         passes_open_files(refinement)
     )
     or
-    exists(PyNodeRefinement refinement | refinement = def |
+    exists(EssaNodeRefinement refinement | refinement = def |
         not closes_file(def) and
         not wraps_file(refinement.getDefiningNode(), refinement.getInput()) and
         var_is_open(refinement.getInput(), open)

python/ql/src/semmle/python/dataflow/TaintTracking.qll

@@ -155,7 +155,7 @@ abstract class TaintKind extends string {
      * For example, if this were a kind of string taint
      * the `result` would be `theStrType()`.
      */
-    ClassValue getType() { result.(ClassObjectInternal).getSource() = this.getClass() }
+    ClassValue getType() { none() }
 
     /**
      * Gets the boolean values (may be one, neither, or both) that
@@ -180,7 +180,10 @@ abstract class TaintKind extends string {
     TaintKind getTaintForIteration() { none() }
 
     predicate flowStep(DataFlow::Node fromnode, DataFlow::Node tonode, string edgeLabel) {
-        this.additionalFlowStepVar(fromnode.asVariable(), tonode.asVariable()) and
+        exists(DataFlowExtension::DataFlowVariable v |
+            v = fromnode.asVariable() and
+            v.getASuccessorVariable() = tonode.asVariable()
+        ) and
         edgeLabel = "custom taint variable step"
     }
 }