Tests: added ssl test for "unexpected eof while reading".

See for details:
http://mailman.nginx.org/pipermail/nginx/2020-March/059162.html

ssl.t

diff --git a/ssl.t b/ssl.t
index d1c1de4..dc6a832 100644
--- a/ssl.t
+++ b/ssl.t
@@ -31,7 +31,7 @@
 plan(skip_all => 'IO::Socket::SSL too old') if $@;
 
 my $t = Test::Nginx->new()->has(qw/http http_ssl rewrite proxy/)
-	->has_daemon('openssl')->plan(26);
+	->has_daemon('openssl')->plan(28);
 
 $t->write_file_expand('nginx.conf', <<'EOF');
 
@@ -316,6 +316,10 @@
 my $r = http($req, socket => $s) || "";
 is(() = $r =~ /(200 OK)/g, 1000, 'pipelined requests');
 
+# OpenSSL 3.0 error "unexpected eof while reading" seen as a critical error
+
+ok(get_ssl_socket(8085), 'ssl unexpected eof');
+
 # close_notify is sent before lingering close
 
 is(get_ssl_shutdown(8085), 1, 'ssl shutdown on lingering close');
@@ -331,6 +335,8 @@
 
 }
 
+like(`grep -F '[crit]' ${\($t->testdir())}/error.log`, qr/^$/s, 'no crit');
+
 ###############################################################################
 
 sub get {