Remove test that pings localhost

Unfortunately, TravisCI does not allow pings.

Author: Namoshek

tests/ServersArePingableTest.php

@@ -23,20 +23,6 @@ public function it_succeeds_when_no_servers_are_given()
         $this->assertTrue($check->check([]));
     }
 
-    /** @test */
-    public function it_succeeds_when_all_all_servers_are_pingable()
-    {
-        $config = ['servers' => [
-            '127.0.0.1',
-            'localhost',
-            ['host' => '127.0.0.1'],
-            ['host' => 'localhost']
-        ]];
-
-        $check = new ServersArePingable();
-        $this->assertTrue($check->check($config));
-    }
-
     /** @test */
     public function it_fails_when_numeric_server_host_is_given()
     {