Remove test that depends on removed code from images

Manifest tests can no longer run and also aren't needed.
All image type manifests are generated and built in the obsuild/images
CI tests and the test function in images
(distro_test_common.TestDistro_Manifest()) has been removed.

test/cases/manifest_tests.sh

@@ -1,35 +0,0 @@
-#!/bin/bash
-set -euo pipefail
-
-MANIFEST_TESTS_RUNNER="/usr/libexec/osbuild-composer-test/osbuild-composer-manifest-tests"
-DNF_JSON_PATH="/usr/libexec/osbuild-composer/dnf-json"
-IMAGE_TEST_CASES_PATH="/usr/share/tests/osbuild-composer/manifests"
-
-WORKING_DIRECTORY=/usr/libexec/osbuild-composer
-ARTIFACTS="${ARTIFACTS:-/tmp/artifacts}"
-
-# Print out a nice test divider so we know when tests stop and start.
-test_divider () {
-    printf "%0.s-" {1..78} && echo
-}
-
-# Provision the software under test.
-/usr/libexec/osbuild-composer-test/provision.sh none
-
-# Change to the working directory.
-cd $WORKING_DIRECTORY
-
-# Run test case.
-TEST_NAME=$(basename "$MANIFEST_TESTS_RUNNER")
-echo
-test_divider
-echo "🏃🏻 Running test: ${TEST_NAME}"
-test_divider
-
-if sudo "$MANIFEST_TESTS_RUNNER" -test.v -manifests-path "$IMAGE_TEST_CASES_PATH" -dnf-json-path "$DNF_JSON_PATH" | tee "${ARTIFACTS}"/"${TEST_NAME}".log; then
-    echo "🎉  Test passed."
-    exit 0
-else
-    echo "🔥 Test failed."
-    exit 1
-fi