external/boringssl: Sync to 45210dd4e21ace9d28cb76b3f83303fcdd2efcce.

This includes the following changes:

https://boringssl.googlesource.com/boringssl/+log/a62dbf88d8a3c04446db833a1eb80a620cb1514d..45210dd4e21ace9d28cb76b3f83303fcdd2efcce

Test: BoringSSL CTS Presubmits.
Change-Id: I2f3cc22fb906078f64bc2af020fa14c3d0875c81
diff --git a/src/ssl/handshake_server.cc b/src/ssl/handshake_server.cc
index bcbd7e2..fa8a241 100644
--- a/src/ssl/handshake_server.cc
+++ b/src/ssl/handshake_server.cc
@@ -441,6 +441,10 @@
     return ssl_hs_error;
   }
 
+  if (ssl->handoff) {
+    return ssl_hs_handoff;
+  }
+
   SSL_CLIENT_HELLO client_hello;
   if (!ssl_client_hello_init(ssl, &client_hello, msg)) {
     OPENSSL_PUT_ERROR(SSL, SSL_R_DECODE_ERROR);