TestMarshalEmbeds fails on i386

[tambry]

I'm packaging this Go package for Debian and CI revealed that TestMarshalEmbeds's result sorts differently on i386 and thus fails.
While i386 is a bit old in the tooth it's still supported and built for in Debian. I've marked it as unsupported for this package however.

[tambry]

It also fails for the same reason on armhf.
There's also a bunch of other failures on s390x.