* rdar://107729601 (Move Error to FoundationPreview)
* rdar://107729601 -- Use stub URL and regular String Encoding
* rdar://107729601 -- Take out RawRepresentable conformance, because changing it was an ABI break
* rdar://107729601 -- Rename Error.swift to CocoaError.swift
Co-authored-by: Tony Parker <anthony.parker@apple.com>