Revert "Configure cache directory"

This reverts commit 967af31.

Author: sebastianbergmann

tests/end-to-end/phar/phpunit.xml

@@ -1,7 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:noNamespaceSchemaLocation="../../../phpunit.xsd"
-         cacheDirectory="../../../.phpunit.cache"
          bootstrap="src/autoload.php"
          failOnRisky="true"
          failOnWarning="true">