Add a standalone parallel iterator for ranges
Add a standalone parallel iterator for ranges

The standalone iterator is much simpler than the leader/follower because
it is only used on bounded ranges and doesn't need to zip with unbounded
ranges.

It currently does nothing special for sublocales, so includes
!localeModelHasSublocales in the where clause.

chizarlicious/chapel,CoryMcCartan/chapel,hildeth/chapel,CoryMcCartan/chapel,chizarlicious/chapel,chizarlicious/chapel,hildeth/chapel,chizarlicious/chapel,CoryMcCartan/chapel,hildeth/chapel,chizarlicious/chapel,CoryMcCartan/chapel,chizarlicious/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,hildeth/chapel,hildeth/chapel,CoryMcCartan/chapel,hildeth/chapel,chizarlicious/chapel,hildeth/chapel