tests/readlink.py

typing: simplify archive.gz writing and drop a few pytype suppressions

I was waiting until 3.8 to use `Literal` to fix this, but there's also the ":"
and "|" characters that are passed along here, meant only for the non-gz archive
types.  But manipulating what the local caller passes is silly- we know we're
writing, so just open it for writing.  As an added bonus, PyCharm stops flagging
the call too (since it doesn't know about pytype suppression comments).

#!/usr/bin/env python3


import errno
import os
import sys

for f in sys.argv[1:]:
    try:
        print(f, '->', os.readlink(f))
    except OSError as err:
        if err.errno != errno.EINVAL:
            raise
        print(f, '->', f, 'not a symlink')

sys.exit(0)