Summary:
Removed remaining path / fs imports from Flipper core.
`expand-tide` needed replacement too, but noticed that it never actually rewrites paths since all use cases were already using absolute paths, so removed it instead.
Reviewed By: aigoncharov
Differential Revision: D33017654
fbshipit-source-id: e12f66ef68b5f9e4279411c94445a2fb87249e9a