Path Alias test fails on php-fpm

The Path Alias Functionality test fails with php-fpm. I see 2 fails running with run-tests.sh and just one running using the web UI.

"Value NULL is TRUE."

There aren't any easy clues to what's going on here in the web UI or run-tests.sh so somebody will have to step through to understand it.

I do have a php-fpm testbot that can be used for debugging.

This blocks progress on php-fpm testbot #2135199: Provide php 5.4 testing on testbots for D8 code without breaking everything else