Backport of 01ddd608b85c.

Issue #27960: Revert state to 675e20c38fdac6, backing out all changes by developed for Issue #12885.

rearrange methodcaller_new so that the main error case does not cause uninitialized memory usage (closes #27783)

Reported by Thomas E. Hybel

Reported by Thomas E. Hybel

Ignore the HTTP_PROXY variable when REQUEST_METHOD environment is set, which
indicates that the script is in CGI mode.

Issue #27568 Reported and patch contributed by Rémi Rampin.

This backports the fix from #16611, per discussion with the release
manager.

This is instead of svn.python.org, whose certificate recently expired, and
whose new certificate uses a different root certificate.

The certificate used at the pythontest server was modifed to set the "basic
constraints" CA flag. This flag seems to be required for test_get_ca_certs_
capath() to work (in Python 3.4+).

Added the new self-signed certificate to capath with the following commands:

cp Lib/test/{selfsigned_pythontestdotnet.pem,capath/}
c_rehash -v Lib/test/capath/
c_rehash -v -old Lib/test/capath/
# Note the generated file names
cp Lib/test/capath/{selfsigned_pythontestdotnet.pem,0e4015b9.0}
mv Lib/test/capath/{selfsigned_pythontestdotnet.pem,ce7b8643.0}

The new server responds with "No route to host" when connecting to port 444.

invalid memory.