Before this, running Chrome was only supported on POSIX-type OS. This commit adds support for running Chrome on Windows, by swapping fork()/exec() with `subprocess.Popen`, which is cross-platform. Linux-specific fixups are implemented via a `preexec_fn`. Also fixes the JSON path generation: the url path separator is `/`, not `os.path.sep`. closes odoo/odoo#83209 Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>