phpunit: Rename package test classes for PHPUnit 11 compat (pt 1) (#42120)

PHPUnit 10+ requires that test class names match the filename, PSR-4
style. This PR renames the test classes and files in packages to end in
`Test` or `_Test`, depending on whether the class names are following
WordPress's underscore-naming convention or are using CamelCase, and
removing redundant `WP_Test_` or `Test_` prefixes.

This also adds our standard Jetpack-Tests ruleset to
tests/.phpcs.dir.xml in the packages, and removes some redundant inline
phpcs:ignore or phpcs:disable directives.

Of note, changed test order in the Connection package broke a test.
Adding some setup/teardown code to clear the affected singleton fixed
it.

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/13637614579

Upstream-Ref: Automattic/jetpack@327f25f

Author: anomiex

composer.json

@@ -5,10 +5,10 @@
 	"license": "GPL-2.0-or-later",
 	"require": {
 		"php": ">=7.2",
-		"automattic/jetpack-blocks": "^3.0.3",
+		"automattic/jetpack-blocks": "^3.0.4-alpha",
 		"automattic/jetpack-assets": "^4.0.9-alpha",
 		"automattic/jetpack-connection": "^6.7.0-alpha",
-		"automattic/jetpack-logo": "^3.0.1",
+		"automattic/jetpack-logo": "^3.0.2-alpha",
 		"automattic/jetpack-status": "^5.0.5-alpha",
 		"automattic/jetpack-sync": "^4.8.2"
 	},