minor #20016 [Form] FormView->isRendered() remove dead code and simplify the flow (taueres)

This PR was merged into the 2.7 branch.

Discussion
----------

[Form] FormView->isRendered() remove dead code and simplify the flow

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

The method `FormView->isRendered()` can be easily simplified by removing useless conditions and statements.
The condition at line 74 is useless because of the composite condition at line 70.
Removed dead code statement at line 84.

Commits
-------

40af42c [Form] FormView->isRendered() remove dead code and simplify the flow

Author: fabpot

src/Symfony/Component/Form/FormView.php

@@ -65,23 +65,17 @@ public function __construct(FormView $parent = null)
      */
     public function isRendered()
     {
-        $hasChildren = 0 < count($this->children);
-
-        if (true === $this->rendered || !$hasChildren) {
+        if (true === $this->rendered || 0 === count($this->children)) {
             return $this->rendered;
         }
 
-        if ($hasChildren) {
-            foreach ($this->children as $child) {
-                if (!$child->isRendered()) {
-                    return false;
-                }
+        foreach ($this->children as $child) {
+            if (!$child->isRendered()) {
+                return false;
             }
-
-            return $this->rendered = true;
         }
 
-        return false;
+        return $this->rendered = true;
     }
 
     /**