(and for * patterns in match)
Since `PhaseDependentFlow` uses the following predicate, that relies on
.getScope() to be present for there to be any importTimeFlow (flow at
toplevel scope), it's important that data-flow nodes implement `.getScope`.
```
private predicate isTopLevel(Node node) { node.getScope() instanceof Module }
```
By implementing getScope, we can now rely on default implementation of
`getEnclosingCallable` in DataFlow::Node:
```
/** Gets the enclosing callable of this node. */
DataFlowCallable getEnclosingCallable() { result = getCallableScope(this.getScope()) }
```
