Refactor how net/data/verify_certificate_chain_unittest/*

net/data/verify_certificate_chain_unittest/generate-target-signed-using-ecdsa.py

-#!/usr/bin/python
-# Copyright (c) 2015 The Chromium Authors. All rights reserved.
-# Use of this source code is governed by a BSD-style license that can be
-# found in the LICENSE file.
-
-"""Certificate chain with a trusted root using RSA, and intermediate using EC,
-and a target certificate using RSA. Verification is expected to succeed."""
-
-import common
-
-# Self-signed root certificate (used as trust anchor). using RSA.
-root = common.create_self_signed_root_certificate('Root')
-
-# Intermediate using an EC key for the P-384 curve.
-intermediate = common.create_intermediate_certificate('Intermediate', root)
-intermediate.set_key(common.get_or_generate_ec_key(
-    'secp384r1', common.create_key_path(intermediate.name)))
-
-# Target certificate contains an RSA key (but is signed using ECDSA).
-target = common.create_end_entity_certificate('Target', intermediate)
-
-chain = [target, intermediate]
-trusted = common.TrustAnchor(root, constrained=False)
-time = common.DEFAULT_TIME
-key_purpose = common.DEFAULT_KEY_PURPOSE
-verify_result = True
-errors = None
-
-common.write_test_file(__doc__, chain, trusted, time, key_purpose,
-                       verify_result, errors)