IterableOnce.copyToArray micro opt
IterableOnce.copyToArray micro opt

xs.length is a bit more expensive than a simple
arraylen op since array type isn't known.

scala/scala,lrytz/scala,martijnhoekstra/scala,scala/scala,scala/scala,martijnhoekstra/scala,lrytz/scala,lrytz/scala,scala/scala,martijnhoekstra/scala,martijnhoekstra/scala,lrytz/scala,scala/scala,scala/scala,lrytz/scala,lrytz/scala,martijnhoekstra/scala,martijnhoekstra/scala