We're naming the inner generator function in the name of the
original async function. This means when people have recursive
await calls it refers to the generator version. Which is fine
if we had a `yield *` (delegate). However, if not it leads to
returning an unresolved generator object.
We can either capture all recursive calls and add a delegate, which
becomes really hard with expressions. I choose to have the name
reserved to the exposed function `retFunction`.
Fixes#2782
I'm extremely stupid and didn't commit as I go. To anyone reading this
I'm extremely sorry. A lot of these changes are very broad and I plan on
releasing Babel 6.0.0 today live on stage at Ember Camp London so I'm
afraid I couldn't wait. If you're ever in London I'll buy you a beer
(or assorted beverage!) to make up for it, also I'll kiss your feet and
give you a back massage, maybe.
