test: Replace TEST_PREVIOUS_RELEASES env var with test_framework option

ci/test/00_setup_env.sh

@@ -33,7 +33,6 @@ export HOST=${HOST:-$("$BASE_ROOT_DIR/depends/config.guess")}
 export USE_BUSY_BOX=${USE_BUSY_BOX:-false}
 export RUN_UNIT_TESTS=${RUN_UNIT_TESTS:-true}
 export RUN_FUNCTIONAL_TESTS=${RUN_FUNCTIONAL_TESTS:-true}
-export TEST_PREVIOUS_RELEASES=${TEST_PREVIOUS_RELEASES:-false}
 export TEST_RUNNER_ENV=${TEST_RUNNER_ENV:-}
 export RUN_FUZZ_TESTS=${RUN_FUZZ_TESTS:-false}
 export CONTAINER_NAME=${CONTAINER_NAME:-ci_unnamed}