Add UnauthenticatedECDH bug test.

This works, but there's enough shared codepaths that it's worth a test to
ensure it stays that way.

Change-Id: I5d5a729811e35832170322957258304213204e3b
Reviewed-on: https://boringssl-review.googlesource.com/1155
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/runner.go b/ssl/test/runner/runner.go
index 27876fa..0b210cd 100644
--- a/ssl/test/runner/runner.go
+++ b/ssl/test/runner/runner.go
@@ -189,6 +189,17 @@
 		shouldFail:         true,
 		expectedLocalError: "client didn't provide a certificate",
 	},
+	{
+		name: "UnauthenticatedECDH",
+		config: Config{
+			CipherSuites: []uint16{TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256},
+			Bugs: ProtocolBugs{
+				UnauthenticatedECDH: true,
+			},
+		},
+		shouldFail:    true,
+		expectedError: ":MISSING_RSA_SIGNING_CERT:",
+	},
 }
 
 func doExchange(tlsConn *Conn, messageLen int) error {