Split the pathname path into a pair [head, tail] where tail is the final part of the path
after the last delimiter and head is everything leading up to that. tail will never contain
a slash.
Parameters
pathname: string
The path to split.
Returns string[]
The split path which is an array of two strings, the path and the
filename.
Split the pathname path into a pair [head, tail] where tail is the final part of the path after the last delimiter and head is everything leading up to that. tail will never contain a slash.