Changeset 49803 for trunk/tests/phpunit/data/feed/wordpress-org-news.xml

Feed: Merge multiple header values to avoid fatal error.

When SimplePie parses HTTP headers, it combines multiple values for the same header into a comma-separated string. WP_SimplePie_File overrides the parsing, but was leaving them as an array instead.

That lead to a fatal error in PHP 8, because other parts of the codebase ended up passing an array to a function that expected a string.

Props david.binda, litemotiv, inc2734, NicolasKulka, hellofromTonya, mbabker, skithund, SergeyBiryukov, desrosj, timothyblynjacobs.
Fixes #51056. See #51956.