Use unique filenames to avoid test conflicts.
Use read_file() instead of io.popen(), to ensures the file is closed.
Use helpers.rmdir(), it is far more robust than lfs.
closes#7911
The flag enables the current local directory set by ":lcd" to be saved
to views which is the current default behaviour. The option can be
removed to disable this behaviour.
closes#7435
vim-patch:8.0.1289