TLS 1.3 requires callers use the callback rather than SSL_get_session.
Change-Id: I2caae70e641b102ce93256c847c178871bf78bac
Reviewed-on: https://boringssl-review.googlesource.com/9076
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>