Fix Dockerfile for JDK 21 CI image

See gh-37359

Author: wilkinsona

ci/images/ci-image-jdk21/Dockerfile

@@ -3,8 +3,7 @@ FROM ubuntu:jammy-20230816
 ADD setup.sh /setup.sh
 ADD get-jdk-url.sh /get-jdk-url.sh
 ADD get-docker-url.sh /get-docker-url.sh
-ADD get-docker-compose-url.sh /get-docker-compose-url.sh
-RUN ./setup.sh java17 java21
+RUN ./setup.sh java8 java21
 
 ENV JAVA_HOME /opt/openjdk
 ENV PATH $JAVA_HOME/bin:$PATH