Fix previous fs test error

Author: tiif

src/shims/unix/fs.rs

@@ -40,7 +40,8 @@ impl FileDescription for FileHandle {
         ecx: &mut MiriInterpCx<'tcx>,
     ) -> InterpResult<'tcx> {
         assert!(communicate_allowed, "isolation should have prevented even opening a file");
-        ecx.read_byte_helper(ptr, bytes.to_vec(), (&mut &self.file).read(bytes), dest)?;
+        let result = (&mut &self.file).read(bytes);
+        ecx.read_byte_helper(ptr, bytes.to_vec(), result, dest)?;
         Ok(())
     }