Fix tests disrupted by re-modelling and stubbing Android 9:

* Account for changed dataflow graph shape using external flow
* Account for BaseBundle only existing as of Android 5
* Properly implement Parcelable, which we previously got away with due to a partial stub
* Restore an Android 11 function that had been added to the Android 9 Context class (I won't get into enforcing the difference in this PR)

java/ql/test/query-tests/security/CWE-502/ParcelableEntity.java

@@ -21,6 +21,9 @@ public class ParcelableEntity implements Parcelable {
         parcel.writeString(GSON.toJson(obj));
     }
 
+    @Override
+    public int describeContents() { return 0; }
+
     public static final Parcelable.Creator CREATOR = new Creator<ParcelableEntity>() {
         @Override
         public ParcelableEntity createFromParcel(Parcel parcel) {