Tolerate early ChangeCipherSpec in DTLS.

This would only come up if the peer didn't pack records together, but
it's free to handle. Notably OpenSSL has a bug where it does not pack
retransmits together.

Change-Id: I0927d768f6b50c62bacdd82bd1c95396ed503cf3
Reviewed-on: https://boringssl-review.googlesource.com/18724
Reviewed-by: David Benjamin <davidben@google.com>
diff --git a/ssl/test/runner/handshake_server.go b/ssl/test/runner/handshake_server.go
index 3e70185..614bb50 100644
--- a/ssl/test/runner/handshake_server.go
+++ b/ssl/test/runner/handshake_server.go
@@ -1819,7 +1819,6 @@
 		c.writeRecord(recordTypeHandshake, postCCSBytes)
 		postCCSBytes = nil
 	}
-	c.flushHandshake()
 
 	if !c.config.Bugs.SkipChangeCipherSpec {
 		ccs := []byte{1}
@@ -1842,11 +1841,11 @@
 		if c.config.Bugs.SendExtraFinished {
 			c.writeRecord(recordTypeHandshake, finished.marshal())
 		}
+	}
 
-		if !c.config.Bugs.PackHelloRequestWithFinished {
-			// Defer flushing until renegotiation.
-			c.flushHandshake()
-		}
+	if !c.config.Bugs.PackHelloRequestWithFinished {
+		// Defer flushing until renegotiation.
+		c.flushHandshake()
 	}
 
 	c.cipherSuite = hs.suite