The problem with `tainted_filelike` not having taint, is that in the call
`ujson.dump(tainted_obj, tainted_filelike)`
there is no PostUpdateNote for `tainted_filelike` :( The reason is that
points-to is not able to resolve the call, so none of the clauses in
`argumentPreUpdateNode` matches
See 08731fc6cf/python/ql/src/semmle/python/dataflow/new/internal/DataFlowPrivate.qll (L101-L111)
Let's deal with that issue in an other PR though
