fix: ignore "Bad file descriptor" on close

[cmhulbert]

Sometimes (seemingly only on MacOs, when accessing blocks over a SMB mount), reading through a FileSystem KVA succeeds, but closing throws a "Bad file descriptor" IOException.
Since the read succeeded, we are willing to ignore this exception.

This has not been thoroughly investigated, but a few things seem to be true that indicate it's related to the SMB mount:

• This doesn't happen right away, but when it does happen, it continues to happen frequently, even across processes (i.e. relaunching the same script/test).
• When it does happen, unmounting and remounting can resolve this, even during the runtime of an application (presuming the application doesn't try to read/write while it's unmounted)

[bogovicj]

Given that the Exception on close is harmless, I think this is the best we can do.