Using cd .. to change back to home directory fails

When attempting to use `cd ..` to change to previous directory, and previous directory is `home`.

1. In blink shell, change directory to iCloud or Documents, from home directory.
2. Then `cd ..`

Error: permission denied

The only way I can find to change to home is to just `cd` without any arguments, or `cd $HOME`

Reproduce the issue in Blink shell by changing from home to iCloud or Documents and running `cd ..`; compare the result with `cd` and `cd $HOME`. Trace the directory-change handling from the `cd` command and verify that returning to home succeeds without a permission-denied error.

Written by the indexing model from the issue text.