Revert "8773 avoid image recreation for running tests"

This reverts commit dd95ed89.

.gitlab-ci.yml

@@ -52,6 +52,7 @@ docker_image:emulator:
   <<: *build_docker_image
 
 unit_test:
+  image: "0xacab.org:4567/leap/bitmask_android/android-ndk:latest"
   stage: test
   script:
     - ./gradlew test