Method calls with by-value params in streams subtrees cause issues

The following symbol seems to cause symbol ownership issues (x not found anymore) when rewriting the Option.getOrElse stream:

```
  def wrap[T](body: => T): Option[T] = Option(body)
  wrap({ val x = 10; Option(x) }) getOrElse 0
```

It is currently detected and mitigated (skipped) by Strategies.hasKnownLimitationOrBug, but needs to be fixed.

Could be related to / duplicate of issue #20.
