tests/functional: Move x86_64 tests into target-specific folder

The tests/functional folder has become quite crowded, thus move the
x86_64 tests into a target-specific subfolder.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20250819112403.432587-23-thuth@redhat.com>
23 files changed