Merge remote-tracking branch 'origin/2.8' into 2.8

* origin/2.8:
  [symfony#8013] revert wrong data provider change
  correct PHP code

Author: weaverryan

form/unit_testing.rst

@@ -196,7 +196,7 @@ allows you to return a list of extensions to register::
             $this->validator
                 ->method('validate')
                 ->will($this->returnValue(new ConstraintViolationList()));
-            $validator
+            $this->validator
                 ->method('getMetadataFor')
                 ->will($this->returnValue(new ClassMetadata(Form::class)));