Use JDK 8 in CI (Fixes: #40005)

 image: debian:buster

 script:

  - apt update

  - apt -y install default-jdk ant ivy git curl

  - apt install -y wget apt-transport-https gnupg

  - wget -qO - https://adoptopenjdk.jfrog.io/adoptopenjdk/api/gpg/key/public | apt-key add -

  - echo "deb https://adoptopenjdk.jfrog.io/adoptopenjdk/deb buster main" | tee /etc/apt/sources.list.d/adoptopenjdk.list

  - apt update

  - apt install -y adoptopenjdk-8-hotspot ant ivy git

  - git submodule init

  - git submodule update

  - ant fetch-metrics-lib

  - ant -lib /usr/share/java resolve

  - ant test

  - ant checks

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