dereferencing registers to access stack variables

dereferencing registers to access stack variables

deref register to access stack variable for `directory_exists/1`
deref register to access stack variable for `directory_files/2`
deref register to access stack variable for `delete_directory/1`
deref register to access stack variable for `delete_file/1`
deref registers to access stack variable for `file_copy/2`
deref register to access stack variable for `file_exists/1`
deref register to access stack variable for `file_size/2`
deref register to access stack variable from `file_time` function
deref register to access stack variable for `make_directory/1`
deref register to access stack variable for `make_directory_path/1`
deref register to access stack variable for `path_canonical/2`
deref registers to access stack variables for `rename_file/2`

Signed-off-by: Thierry Marianne <[email protected]>