runner: Move Finished special-case into dtlsWriteRecord.

We actually don't really care about this special-case since we only test client
full handshakes where the runner sends the second Finished not the shim
(otherwise the overlap logic and retransmitting on every fragment would
probably break us), but it should probably live next to the fragmentation
logic.

Change-Id: I54097d84ad8294bc6c42a84d6f22f496e63eb2a8
Reviewed-on: https://boringssl-review.googlesource.com/3763
Reviewed-by: Adam Langley <agl@google.com>
3 files changed