FileSystemInfo.LastWriteTimeUtc throws on Linux if folder doesn't exist

[mregen]

FileSystemInfo.LastWriteTimeUtc behaves different on Windows and Ubuntu 16.04:

see: OPCFoundation/UA-.NETStandard#112

Set FileSystemInfo to a path that doesn't exist, then call LastWriteTimeUtc.

On Windows it returns something like 1.1.1600,

On Linux it throws exception

expected: windows behaviour or at least similar behaviour on both OS.

[ianhays]

Hey @mregen, we've already got an issue for this (https://github.com/dotnet/corefx/issues/1728) so I'm going to close this one as it is a duplicate. Feel free to re-open 1728 or comment there if you'd like to continue the discussion.

Thanks!