restore the overriden locale on tearDown - avoid interfering with any configured value

Previously this change was not resetting the locale after changing it to
'en' - which affected other tests which relied on this value being the
configured value (however it was configured).

This mirrors the pattern used for the timezone, storing it to be reset
on tearDown.

Author: rodnaph

Test/ConstraintValidatorTestCase.php

@@ -58,6 +58,7 @@ abstract class ConstraintValidatorTestCase extends TestCase
     protected $propertyPath;
     protected $constraint;
     protected $defaultTimezone;
+    private $defaultLocale;
 
     private function doSetUp()
     {
@@ -76,6 +77,7 @@ private function doSetUp()
         $this->validator = $this->createValidator();
         $this->validator->initialize($this->context);
 
+        $this->defaultLocale = \Locale::getDefault();
         \Locale::setDefault('en');
 
         $this->setDefaultTimezone('UTC');
@@ -84,6 +86,8 @@ private function doSetUp()
     private function doTearDown()
     {
         $this->restoreDefaultTimezone();
+
+        \Locale::setDefault($this->defaultLocale);
     }
 
     protected function setDefaultTimezone($defaultTimezone)