Test that we tolerate server-sent supported groups.

I should have added this test in
https://boringssl-review.googlesource.com/10320. This is necessary in
TLS 1.3 and spec compliance and TLS 1.2 to tolerate some broken servers.

Change-Id: Ibb52eaa1e370062f83e84856ef7f1c2c79d6a5d3
Reviewed-on: https://boringssl-review.googlesource.com/21124
Commit-Queue: Steven Valdez <svaldez@google.com>
Reviewed-by: Steven Valdez <svaldez@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/ssl/test/runner/common.go b/ssl/test/runner/common.go
index dc4055e..3991870 100644
--- a/ssl/test/runner/common.go
+++ b/ssl/test/runner/common.go
@@ -1386,6 +1386,12 @@
 	// empty slice, no extension will be sent.
 	SendSupportedPointFormats []byte
 
+	// SendServerSupportedCurves, if true, causes the server to send its
+	// supported curves list in the ServerHello (TLS 1.2) or
+	// EncryptedExtensions (TLS 1.3) message. This is invalid in TLS 1.2 and
+	// valid in TLS 1.3.
+	SendServerSupportedCurves bool
+
 	// MaxReceivePlaintext, if non-zero, is the maximum plaintext record
 	// length accepted from the peer.
 	MaxReceivePlaintext int