Tests: added $ssl_server_name checks to stream_ssl_certificate.t.

Previously, the checks were exempted from stream tests, since the stream
module did not implement a server name callback, so OpenSSL 1.1.1 didn't
save it to the session.  Since 7e8bcba6d039 (1.15.10), it's implemented.
This change is thereby a diff reduction to ssl_certificate.t.

stream_ssl_certificate.t

diff --git a/stream_ssl_certificate.t b/stream_ssl_certificate.t
index 56f6186..9d63092 100644
--- a/stream_ssl_certificate.t
+++ b/stream_ssl_certificate.t
@@ -162,13 +162,9 @@
 my ($s, $ssl) = get('default', 8080);
 my $ses = Net::SSLeay::get_session($ssl);
 
-like(get('default', 8080, $ses), qr/:r/, 'session reused');
-
-# do not check $ssl_server_name, since stream doesn't install SNI callback
-# see for more details: https://github.com/openssl/openssl/issues/7014
-
-like(get('default', 8081, $ses), qr/:r/, 'session id context match');
-like(get('default', 8082, $ses), qr/:\./, 'session id context distinct');
+like(get('default', 8080, $ses), qr/default:r/, 'session reused');
+like(get('default', 8081, $ses), qr/default:r/, 'session id context match');
+like(get('default', 8082, $ses), qr/default:\./, 'session id context distinct');
 
 # errors