Probably leftover from copying the test file to create the ref.
This included a circular reference claiming the ref was its own ref.

Remove unnecessary decorations only present in the test but not in the
ref

* Remove inconsistencies in unessential decorations between test and ref
* Correct manual calculations of letter spacing in the "control" block
* Fix application of white-space property in ref file

* Remove unnecessary decorations

* Remove the width constraint: it causes line breaks and these interfere
with the presence of letter-spacing in a way that isn't tracked by that
test. Other tests take care of end-of-line letter-spacing.

* Make assert consistent with the test (and the spec)
* Remove unnecessary decorations
* Complete the ref to match the test
* Add support file

* Don't use proprietary properties
* Remove dead code
* Add missing ref file

* Remove unnecessary decorations
* Delete leftover code
* Set up the ref file

There are plenty of test checking whether letter spacing adds a space at
the end of the line or not. Confirming that is not the point of these
two tests, especially given that that is still a controvertial topic,
while the point of this test is not.

This commit makes the tests work regardless of how end of lines are
handled.