Become strict about notices and warnings

Since PHPUnit 10, it is possible to display details when notices and
warnings happen, and to fail the test suite on notice.
failOnWarning is older than that.

phpunit.xml.dist

@@ -14,6 +14,10 @@
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
          colors="true"
+         displayDetailsOnTestsThatTriggerNotices="true"
+         displayDetailsOnTestsThatTriggerWarnings="true"
+         failOnNotice="true"
+         failOnWarning="true"
          failOnRisky="true"
          bootstrap="./tests/Doctrine/Tests/TestInit.php"
          cacheDirectory=".phpunit.cache"