spack audit: fix spurious failures for target/platform conflicts (#28860)

var/spack/repos/builtin.mock/packages/unconstrainable-conflict/package.py

@@ -0,0 +1,16 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+class UnconstrainableConflict(Package):
+    """Package with a conflict whose trigger cannot constrain its constraint."""
+
+    homepage = "http://www.example.com"
+    url      = "http://www.example.com/unconstrainable-conflict-1.0.tar.gz"
+
+    version('1.0', '0123456789abcdef0123456789abcdef')
+
+    # Two conflicts so there's always one that is not the current platform
+    conflicts('target=x86_64', when='platform=darwin')
+    conflicts('target=aarch64', when='platform=linux')