Foundation: map `ECANCELED` properly for Windows
Foundation: map `ECANCELED` properly for Windows

This is generally not a very helpful constant for Windows, however, it
can be passed from Dispatch in some cases.  Lets just provide the
mapping for the Windows version.

apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation,apple/swift-corelibs-foundation