test/fuse_dlm, test/fuse_p2p/peer_chunk_sharing_test.go and
unmaintained/check_disk_size use syscall.Flock, syscall.Stat_t and
syscall.Statfs, which do not exist on Windows. Without constraints,
gopls and go vet on a Windows host report them as undefined.
fuse_p2p/framework_test.go already carries `linux || darwin`; the FUSE
test files now match it. check_disk_size uses the same constraint as
weed/stats/disk_supported.go.
Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>