[+++][FIX][Validator] Fix an issue with Symfony 3.3

Symfony 3.3 remove the Content-Type and Content-Length headers when the status code is 204 or 304 or in the informational range (1xx). This commit handle those cases.

src/Test/SwaggerValidator.php

@@ -85,7 +85,7 @@ public function validateResponseFor(ResponseInterface $actual, $method, $path, $
 
         $contentType = $actual->getHeader('Content-Type');
 
-        if (!array_intersect($contentType, $produces)) {
+        if ($this->statusCodeMeetRequirements($code) && !array_intersect($contentType, $produces)) {
             throw ContentTypeException::fromInvalidContentType($contentType, $produces);
         }
 
@@ -131,4 +131,17 @@ private function getOperation($method, $path)
             ->getOperationFor($method)
         ;
     }
+
+    /**
+     * Checks whether the status code is not 204 or 304 or is not in the informational range. Such responses does not
+     * have any content nor Content-Type headers.
+     *
+     * @param int $code
+     *
+     * @return bool
+     */
+    private function statusCodeMeetRequirements($code)
+    {
+        return !in_array($code, [204, 304]) && substr((string) $code, 0, 1) !== '1';
+    }
 }