Summary:
Previously, `visitContiguousRanges` for fallback F14 sets did not build and
`visitAllocationClasses` was invoking the visitor with the wrong order.

This diff fixes these bugs and moves the tests so that it'll get run regardless
of whether vector intrinsics are available.

Reviewed By: nbronson

Differential Revision: D8542771

fbshipit-source-id: 3aee3ab9e3278110ec8349bd9c858d19df779eb1