Call for Testing: Lazily Evaluate Translation Strings

While attempting to localize REST API responses (#44758), Gutenberg contributors identified that there was an order-of-operations issue preventing locale information from being properly passed in via the REST API. @schlessera had previously worked on a performance optimization patch to lazily translate strings on demand, which was found to also permit locale information to be set before computing the strings, unblocking the Gutenberg issue.

To get this patch landed quickly, we request assistance from interested contributors to test and validate the patch on ticket #41305.

There has been some recent discussion about additional performance and memory usage optimizations, but I believe the solution proposed in the latest patches is close to being satisfactory. It just needs a little further testing and validation from committers and contributors familiar with translation handling and PHP performance before we can comfortably land the patch.

We request input by the end of this working week, if possible, to help remove the blocker to further Gutenberg localization work. Thank you!