tests/testlib/sigpipe-worker.py

automation: delete code related to Python 2.7 support

The building of Inno and WiX installers took a python_version argument
that allowed us to specify "2" or "3" for the major Python version. Since
we no longer support Python 2, we can delete this argument and everything
feeding into it.

Differential Revision: https://phab.mercurial-scm.org/D12264

#!/usr/bin/env python3
#
# This is literally `cat` but in python, one char at a time.
#
# see sigpipe-remote.py for details.
from __future__ import print_function

import io
import os
import sys


if isinstance(sys.stdout.buffer, io.BufferedWriter):
    print('SIGPIPE-WORKER: script need unbuffered output', file=sys.stderr)
    sys.exit(255)

while True:
    c = os.read(sys.stdin.fileno(), 1)
    os.write(sys.stdout.fileno(), c)