Better fix for Fuchsia

Author: hkratz

library/std/src/sys/unix/fs.rs

@@ -1628,20 +1628,13 @@ mod remove_dir_impl {
         target_os = "solaris",
         target_os = "illumos",
         target_os = "haiku",
-        target_os = "vxworks"
+        target_os = "vxworks",
+        target_os = "fuchsia"
     ))]
     fn is_dir(_ent: &DirEntry) -> Option<bool> {
         None
     }
 
-    #[cfg(target_os = "fuchsia")]
-    fn is_dir(ent: &DirEntry) -> Option<bool> {
-        match ent.entry.d_type {
-            libc::DT_DIR => Some(true),
-            _ => Some(false),
-        }
-    }
-
     #[cfg(not(any(
         target_os = "solaris",
         target_os = "illumos",