Revert "Drop retransmits in DTLS tests."

This reverts commit c67a3ae6babb8accceb6854ec5167cd8b1d19e2f. With a
deterministic clock, we can now go back to being strict about retransmits. Our
tests will now require that the shim only retransmit when we expect it to.

Change-Id: Iab1deb9665dcd294790c8253d920089e83a9140c
Reviewed-on: https://boringssl-review.googlesource.com/3211
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/conn.go b/ssl/test/runner/conn.go
index d4a6817..1c64c6a 100644
--- a/ssl/test/runner/conn.go
+++ b/ssl/test/runner/conn.go
@@ -756,11 +756,8 @@
 		if typ != want {
 			// A client might need to process a HelloRequest from
 			// the server, thus receiving a handshake message when
-			// application data is expected is ok. Moreover, a DTLS
-			// peer who sends Finished second may retransmit the
-			// final leg. BoringSSL retrainsmits on an internal
-			// timer, so this may also occur in test code.
-			if !c.isClient && !c.isDTLS {
+			// application data is expected is ok.
+			if !c.isClient {
 				return c.in.setErrorLocked(c.sendAlert(alertNoRenegotiation))
 			}
 		}
@@ -1096,9 +1093,9 @@
 				// Soft error, like EAGAIN
 				return 0, err
 			}
-			if c.hand.Len() > 0 && !c.isDTLS {
+			if c.hand.Len() > 0 {
 				// We received handshake bytes, indicating the
-				// start of a renegotiation or a DTLS retransmit.
+				// start of a renegotiation.
 				if err := c.handleRenegotiation(); err != nil {
 					return 0, err
 				}