Check for RFC 5746 TLS extension

RFC 5746 allows you to either include a signaling cipher suite or a TLS
extension. However, since TLS API has no way to indicate or check that
a certain TLS extension is used, we insert it into the cipher suites
we see to check against the enabled cipher suites.

(cherry picked from commit 81885494e46596c796cdcb5037b91d92915b65a7)

Bug: 24602368
Change-Id: I06422b9a90f47bb5ffa10ef614233d856773d336
2 files changed