Drop remnants of HHVM from tests

It was removed from Travis in c479cdd42f

tests/Generator/PeclUuidTestCase.php

@@ -15,10 +15,4 @@ class PeclUuidTestCase extends TestCase
 {
     protected $uuidString = 'b08c6fff-7dc5-e111-9b21-0800200c9a66';
     protected $uuidBinary = '62303863366666662d376463352d653131312d396232312d303830303230306339613636';
-
-    protected function setUp()
-    {
-        $this->skipIfHhvm();
-        parent::setUp();
-    }
 }