In `x.arg = TAINTED_STRING` there is a store step to the attribute `arg`
of `x`. In our taint modeling, we allow _any_ store step with the code
below. This means that we also say there is a taint-step directly from
`TAINTED_STRING` to `x` :|
```codeql
// construction by literal
// TODO: Not limiting the content argument here feels like a BIG hack, but we currently get nothing for free :|
DataFlowPrivate::storeStep(nodeFrom, _, nodeTo)
```
