Tests: removed ngx_parse_inet6_url() "::" test from proxy.t.

It results in WSAEADDRNOTAVAIL on win32, be the connection errors detected,
which leads to connect() alert.  On other systems, connect() is successful
but it uses the default port (80), which is out of documented ports range.
diff --git a/proxy.t b/proxy.t
index 964883c..fd661f8 100644
--- a/proxy.t
+++ b/proxy.t
@@ -23,7 +23,7 @@
 select STDERR; $| = 1;
 select STDOUT; $| = 1;
 
-my $t = Test::Nginx->new()->has(qw/http proxy/)->plan(31);
+my $t = Test::Nginx->new()->has(qw/http proxy/)->plan(30);
 
 $t->write_file_expand('nginx.conf', <<'EOF');
 
@@ -111,7 +111,6 @@
 like(http_get('/var?b=127.0.0.1:' . port(8081) . '/'), qr/SEE-THIS/,
 	'proxy with variables');
 like(http_get('/var?b=u/'), qr/SEE-THIS/, 'proxy with variables to upstream');
-ok(http_get("/var?b=[::]"), 'proxy with variables - no ipv6 port');
 
 like(http_get('/timeout'), qr/200 OK/, 'proxy connect timeout');