Fix Issue 11336 - ElementType does not support types with disabled postb...

...lits

The root issue was an old hack which tested via a function a return by value. No postblit => no return by value.

I was able to work around the entire hack by simply using @denis-sh 's `lvalueOf`. A really neat thing about `lvalueOf` is that it has the whole `inout` hack "integrated" into it, so the hack can be entirely removed from the calling code. No hack => no function => no problem :)

The makes the final code trivial and straight forward. I'll really loving this `lvalueOf` trait.

@denis-sh : You introduced the hack (AFAIK), and implemented `lvalueOf`: Do you see anything here I might have missed?

If this is correct, I think it's time to do a pass on all of `range`/`traits` and deploy `lvalueOf`...