Fix Vintage test fixture compilation using Groovy 2.x

Author: marcphilipp

.github/actions/setup-test-jdk/action.yml

@@ -9,6 +9,13 @@ runs:
   using: "composite"
   steps:
     - uses: actions/setup-java@3a4f6e1af504cf6a31855fa899c6aa5355ba6c12 # v4.7.0
+      with:
+        distribution: ${{ inputs.distribution }}
+        java-version: 8
+        check-latest: true
+    - shell: bash
+      run: echo "JDK8=$JAVA_HOME" >> $GITHUB_ENV
+    - uses: actions/setup-java@7a6d8a8234af8eb26422e24e3006232cccaa061b # v4
       with:
         distribution: ${{ inputs.distribution }}
         java-version: 17

gradle.properties

@@ -20,7 +20,7 @@ org.gradle.jvmargs=-Xmx1g -XX:MaxMetaspaceSize=512m -XX:+HeapDumpOnOutOfMemoryEr
 org.gradle.caching=true
 org.gradle.parallel=true
 org.gradle.configuration-cache.parallel=true
-org.gradle.java.installations.fromEnv=JDK17,JDK21,JDK23,JDK24,JDK25
+org.gradle.java.installations.fromEnv=JDK8,JDK17,JDK21,JDK23,JDK24,JDK25
 org.gradle.kotlin.dsl.allWarningsAsErrors=true
 
 # Test Distribution