DTLS fragments may not be split across two records.

See also upstream's 9dcab127e14467733523ff7626da8906e67eedd6. The root problem
is dtls1_read_bytes is wrong, but we can get the right behavior now and add a
regression test for it before cleaning it up.

Change-Id: I4e5c39ab254a872d9f64242c9b77b020bdded6e6
Reviewed-on: https://boringssl-review.googlesource.com/5123
Reviewed-by: Adam Langley <agl@google.com>
4 files changed