After discussing it in the issue, we have agreed to apply
the new phpunit_util::normalise_line_endings() method to
all the remaining cases (within tests!) where the manual
replacement was being done. This commits achieves that.
Note that I've looked for both str_replace() and preg_replace()
cases, but only the former had cases worth converting. All the
later ones are different and cannot be replaced by the new
utility method.