Repair wp/5.9 branch Actions: Replace wp-env's database check with a MariaDB health check - #84412

Part of #82934.

What?

Ports #75046 to this branch's wp-env: it waits for MariaDB with a Docker health check instead of wp db check.

• mysql and tests-mysql get a health check, and wordpress/tests-wordpress start only once their database is healthy (condition: service_healthy).
• wp-env start no longer runs wp db check (or its retry loop and extra sleep), and starts both databases together. wp-env clean starts only the database it resets.
• The health check is Env: Add an option to choose the MariaDB version #83751's version (see How?). MARIADB_AUTO_UPGRADE is set so existing databases get the user healthcheck.sh needs.
• CHANGELOG entry, and the README note about wp db and MariaDB before 11.4 now says wp-env start isn't affected.

Why?

wp db check runs mariadb-check from the wordpress:cli image, whose MariaDB 11.8 client requires TLS, and WP-CLI passes --no-defaults so that can't be turned off. MariaDB before 11.4 has no TLS by default, so the check fails with SSL is required, but the server does not support it and wp-env start stops. The next PR in this stack, #84411, pins MariaDB 10.6, so without this change every job that starts wp-env would fail.

How?

The depends_on, start and clean changes follow #75046, adapted to this branch's files. The health check comes from #83751 because #75046's unconditional healthcheck.sh doesn't work on every MariaDB version wp-env can select: 10.2 and 10.3 lack the healthcheck user, and pre-2022 images and old patch tags lack the script. It runs healthcheck.sh --connect --innodb_initialized when both the script and .my-healthcheck.cnf exist, and otherwise pings 127.0.0.1 over TCP with mariadb-admin or mysqladmin, whichever the image has. Unlike wp/6.3 and newer, this branch's wp-env uses the stock wordpress:cli image without a generated Dockerfile, so #83751's client wrappers can't be added; wp db commands still fail below 11.4, as the README notes.

#75046's compose tests and #83751's health check tests are ported (the latter run the command against stub scripts, skipped on Windows; replaceAll became .split().join() for Node 14).

Verified locally: wp-env start with MariaDB 10.6 brings both databases up healthy and installs WordPress in both environments. With mariadb:10.3, both become healthy through the ping fallback.

Use of AI Tools

This PR was created by Claude Code under my supervision. All code should be treated as AI-produced and not yet reviewed by a human until this PR is marked Ready for Review.