Fixing BoringSSL on iOS

This adds the final changes to cert_verify_proc_ios and various tests
in order to prepare for the switchover from NSS to BoringSSL on iOS.

BUG=591545

Review URL: https://codereview.chromium.org/1871043003

Cr-Commit-Position: refs/heads/master@{#386819}
6 files changed