Sort the filenames in TestWithFiles to ensure a stable hash
Sort the filenames in TestWithFiles to ensure a stable hash

PiperOrigin-RevId: 326313077
Change-Id: I91260712dba441efd94dd88d6abdd83c4563ae3a

GoogleCloudPlatform/buildpacks,GoogleCloudPlatform/buildpacks,GoogleCloudPlatform/buildpacks,GoogleCloudPlatform/buildpacks