Run tests on PHP 8.4 and update test suite

Author: PaulRotmann

.github/workflows/ci.yml

@@ -41,7 +41,7 @@ jobs:
 
   PHPUnit-hhvm:
     name: PHPUnit (HHVM)
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-20.04
     continue-on-error: true
     steps:
       - uses: actions/checkout@v2