Revert resolution related methods to not use Deferred

Author: jsor

src/React/Promise/Deferred.php

@@ -48,10 +48,7 @@ public function then($fulfilledHandler = null, $errorHandler = null, $progressHa
     public function resolve($result = null)
     {
         if (null !== $this->completed) {
-            $deferred = new static();
-            $deferred->resolve($result);
-
-            return $deferred->promise();
+            return Util::promiseFor($result);
         }
 
         $this->completed = Util::promiseFor($result);

src/React/Promise/When.php

@@ -6,10 +6,7 @@ class When
 {
     public static function resolve($promiseOrValue)
     {
-        $deferred = new Deferred();
-        $deferred->resolve($promiseOrValue);
-
-        return $deferred->promise();
+        return Util::promiseFor($promiseOrValue);
     }
 
     public static function reject($promiseOrValue)