Add test for renego client_version quirk.

In upstream's f4e1169341ad1217e670387db5b0c12d680f95f4, the client_version was
made constant across renegotiations, even if the server negotiated a lower
version. NSS has the same quirk, reportedly for SChannel:

https://code.google.com/p/chromium/codesearch#chromium/src/net/third_party/nss/ssl/ssl3con.c&sq=package:chromium&l=5103

Add a test to ensure we do not regress this.

Change-Id: I214e062463c203b86a9bab00f8503442e1bf74fe
Reviewed-on: https://boringssl-review.googlesource.com/2405
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/runner.go b/ssl/test/runner/runner.go
index 79f8ee0..7356388 100644
--- a/ssl/test/runner/runner.go
+++ b/ssl/test/runner/runner.go
@@ -2109,6 +2109,16 @@
 		},
 		renegotiateCiphers: []uint16{TLS_RSA_WITH_RC4_128_SHA},
 	})
+	testCases = append(testCases, testCase{
+		name:        "Renegotiate-SameClientVersion",
+		renegotiate: true,
+		config: Config{
+			MaxVersion: VersionTLS10,
+			Bugs: ProtocolBugs{
+				RequireSameRenegoClientVersion: true,
+			},
+		},
+	})
 }
 
 func addDTLSReplayTests() {