fix: Add missing functions from restored fs.Stats

[phated]

In my project, I noticed that a library that used isCharacterDevice on a file from the snapshot crashed. This adds the missing functions as noops (and I made isFIFO use noop so it was clearer).

I thought about making these mirror their files that were included, but I don't think either makes sense within the virtual fs. Please correct me if I'm wrong.

[robertsLando]

@phated wouldn't it make more sense to return false instead of using noop there? Otherwise simply create a function returnFalse and use that there?

[phated]

@robertsLando that's what noop does. It's used for Dirent prototype too