Tuple optimizations disablement.
ceylon/ceylon.language#478: Change compiler to use tuple factory method instead of a Tuple constructor for the transformation of tuple instantiation such as [foo, *sequence].
ceylon/ceylon.language#478, #1670: Remove the static Tuple optimization since the Tuple's array won't contain all its elements if it has a non-empty tail.
Rewrite the dynamic tuple optimization so that $getArray$() can return null (when there's a non-empty tail) which means we have to take the "slow" path of normal Iterator iteration. I say "slow" because it currently appears that this whole Tuple iteration optimization thing now makes iterating a Tuple slower, so I'll probably be taking this optimization out in a commit or two.
Update sources now that the static Tuple optimization has been removed and for tuple creation via factory method.
Improve benchmark