fs: remove os.FileInfo from fs.ExtendedFileInfo

Only the `Sys()` value from os.FileInfo is kept as field `sys` to
support Windows. The os.FileInfo removal ensures that for values like
`ModTime` that existed in both data structures there's no more confusion
which value is actually used.

internal/fs/stat.go

@@ -8,7 +8,8 @@ import (
 // ExtendedFileInfo is an extended stat_t, filled with attributes that are
 // supported by most operating systems. The original FileInfo is embedded.
 type ExtendedFileInfo struct {
-	os.FileInfo
+	Name string
+	Mode os.FileMode
 
 	DeviceID  uint64 // ID of device containing the file
 	Inode     uint64 // Inode number
@@ -23,6 +24,9 @@ type ExtendedFileInfo struct {
 	AccessTime time.Time // last access time stamp
 	ModTime    time.Time // last (content) modification time stamp
 	ChangeTime time.Time // last status change time stamp
+
+	// nolint:unused // only used on Windows
+	sys any // Value returned by os.FileInfo.Sys()
 }
 
 // ExtendedStat returns an ExtendedFileInfo constructed from the os.FileInfo.