Add tests for client version negotiation and session resumption.

BUG=chromium:417134

Change-Id: If5914be98026d899000fde267b2d329861ca3136
Reviewed-on: https://boringssl-review.googlesource.com/1822
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/ssl/test/runner/common.go b/ssl/test/runner/common.go
index 7dbc1f0..cf244bc 100644
--- a/ssl/test/runner/common.go
+++ b/ssl/test/runner/common.go
@@ -460,6 +460,10 @@
 	// ALPN on the server. This is to test that server preference
 	// of ALPN works regardless of their relative order.
 	SwapNPNAndALPN bool
+
+	// AllowSessionVersionMismatch causes the server to resume sessions
+	// regardless of the version associated with the session.
+	AllowSessionVersionMismatch bool
 }
 
 func (c *Config) serverInit() {