MakeDeclaredNamesUnique is incorrect when function expression names are shadowed by parameters

This is a super-specific issue, but it has the potential to cause problems when we move name uniquification earlier, since types will potentially get bound to the wrong names.

The following code demonstrates the issue:
```js
var f; (function f(f) {})
```

In this case, there are effectively four nested scopes: the enclosing scope that declares the `var f`, the function name scope, which declares `function f` that shadows the `var f`, the parameter list scope that declares the parameter `(f)` that immediately shadows the function name, and the function body scope, which is empty here. I don't fully understand why the parameter list needs its own scope. The compiler elides the 2nd scope that holds only the function name. As a result, there's no scope for the compiler to hang this name on, so it doesn't end up being a var anywhere.

I'm currently leaning toward adding some special handling in `ContextualRenamer` and `ContextualRenameInverter` to detect this specific case and give it an arbitrary (invertible) name.