Add server-side FallbackSCSV tests.

Assert that inappropriate fallbacks are detected, but if the client_version
matches the server's highest version, do not abort the handshake.

Change-Id: I9d72570bce45e1eb23fc2b74a3c5fca10562e573
Reviewed-on: https://boringssl-review.googlesource.com/1373
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/common.go b/ssl/test/runner/common.go
index 1cfdda9..4f34ce4 100644
--- a/ssl/test/runner/common.go
+++ b/ssl/test/runner/common.go
@@ -387,6 +387,10 @@
 	// SendV2ClientHello causes the client to send a V2ClientHello
 	// instead of a normal ClientHello.
 	SendV2ClientHello bool
+
+	// SendFallbackSCSV causes the client to include
+	// TLS_FALLBACK_SCSV in the ClientHello.
+	SendFallbackSCSV bool
 }
 
 func (c *Config) serverInit() {