Find actors which can be inlined

```
ACTOR Future bar( LargeObject x ) {
wait(delay(1));
x.x++;
return void();
}

ACTOR Future foo( LargeObject x ) {
wait( bar(x) );
return void();
}
```

In this example the `bar` could be inlined to avoid copying the object `x`. Ideally the actor compiler could identify opportunities to do this optimization itself, however even if that is not possible we could at least look for actors which are constructed in wait statements and manually optimize locations which cause a lot of copying.

Start with the actor compiler and the example pattern where bar(x) is constructed inside wait. Determine whether the compiler can identify actors suitable for inlining to avoid copying LargeObject values, or whether affected locations must be found manually. Done means a defined approach for identifying and optimizing these copying opportunities.

Written by the indexing model from the issue text.