Add test coverage for normal alert parsing.

We have test coverage for invalid alerts, but not for normal ones on the DTLS
side.

Change-Id: I359dce8d4dc80dfa99b5d8bacd73f48a8e4ac310
Reviewed-on: https://boringssl-review.googlesource.com/3291
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/common.go b/ssl/test/runner/common.go
index f5ceefc..a253cb9 100644
--- a/ssl/test/runner/common.go
+++ b/ssl/test/runner/common.go
@@ -475,8 +475,9 @@
 	// two records.
 	FragmentAlert bool
 
-	// SendSpuriousAlert will cause an spurious, unwanted alert to be sent.
-	SendSpuriousAlert bool
+	// SendSpuriousAlert, if non-zero, will cause an spurious, unwanted
+	// alert to be sent.
+	SendSpuriousAlert alert
 
 	// RsaClientKeyExchangeVersion, if non-zero, causes the client to send a
 	// ClientKeyExchange with the specified version rather than the