Test that signature_algorithm preferences are enforced.

Both on the client and the server.

Change-Id: I9892c6dbbb29938154aba4f53b10e8b5231f9c47
Reviewed-on: https://boringssl-review.googlesource.com/4071
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/common.go b/ssl/test/runner/common.go
index a9c5083..5cc8e42 100644
--- a/ssl/test/runner/common.go
+++ b/ssl/test/runner/common.go
@@ -675,6 +675,10 @@
 	// IgnorePeerCipherPreferences, if true, causes the peer's cipher
 	// preferences to be ignored.
 	IgnorePeerCipherPreferences bool
+
+	// IgnorePeerSignatureAlgorithmPreferences, if true, causes the peer's
+	// signature algorithm preferences to be ignored.
+	IgnorePeerSignatureAlgorithmPreferences bool
 }
 
 func (c *Config) serverInit() {