Shuffle things around; add PreopenList.findByPath method

This commit removes `std.os.openatWasi` function, and renames it to
`std.os.wasi.openat`. Additionally, the added `PreopenList.findByPath`
method allows querying the list for a matching preopen by path.
d4c33129cfJakub Konka committed on 5/5/2020, 1:08:52 PMparentdd23835
3 files changedLine totals unavailable