PostfixDeref: translation using map construct does not work with push, etc

Using `map` to translate the postfix subscripts does not work with `push`,
`pop`, `shift`, `unshift`, `splice`, and other built-ins that modify the
parameter as the `map` is using a copy.

Perhaps the translation of
```perl
$foo->$*
```
should be
```perl
${ $foo }
```
instead of the current
```perl
(map $$_, $foo)[0]
```
