Add test builds for PHP 8.2 #20184

Summary

Currently test suites are run against PHP 7.2 and PHP 8.1.

With PHP 8.2 now entering mainstream usage, once we've migrated to github actions we should run all tests against PHP8.2.

This can probably replace the PHP 8.1 build, so we'd test against the lowest (7.2) and highest (8.2) supported PHP versions.

Let's try doing that one, once we migrated to GitHub actions