Merge branch '6.4' into 7.1

* 6.4:
  Make more data providers static
  fix merge
  Mutate remaining data providers to static ones

Tests/Normalizer/AbstractObjectNormalizerTest.php

@@ -1191,7 +1191,7 @@ public function testDenormalizeBooleanTypesWithNotMatchingData(array $data, stri
         $normalizer->denormalize($data, $type);
     }
 
-    public function provideBooleanTypesData()
+    public static function provideBooleanTypesData()
     {
         return [
             [['foo' => true], FalsePropertyDummy::class],