Python: simplify according to review comments

python/ql/src/experimental/dataflow/internal/DataFlowPrivate.qll

@@ -335,7 +335,7 @@ DataFlowCallable prunedViableImplInCallContext(DataFlowCall call, DataFlowCall c
  */
 predicate isImmutableOrUnobservable(Node n) { none() }
 
-int accessPathLimit() { result = 3 }
+int accessPathLimit() { result = 5 }
 
 /** Holds if `n` should be hidden from path explanations. */
 predicate nodeIsHidden(Node n) { none() }

python/ql/src/experimental/dataflow/internal/DataFlowPublic.qll

@@ -142,10 +142,4 @@ class BarrierGuard extends Expr {
  */
 class Content extends string {
   Content() { this = "Content" }
-
-  /** Gets the type of the object containing this content. */
-  DataFlowType getContainerType() { none() }
-
-  /** Gets the type of this content. */
-  DataFlowType getType() { none() }
 }