This implements stat device and inode for WASI and GOOS=js, though it
does not implement the host side for windows, yet. Doing windows
requires plumbing as the values needed aren't exposed in Go. When we
re-do the syscallfs file type to have a stat method, we can address that
glitch. Meanwhile, I can find no Go sourcebase that does any better,
though the closest is the implementation details of os.SameFile.
I verified this with wasi-testsuite which now passes all but 1 case
which is unrelated (we haven't yet implemented `lseek`).
Signed-off-by: Adrian Cole <adrian@tetrate.io>