TestBuild/X86Linux fails on aarch64

[QuLogic]

Of course, this is running with qemu since it's cross-architecture, but I believe this used to work in the past. Now it fails with something to do with bdwgc:

=== CONT  TestBuild/X86Linux/filesystem.go
GC Warning: Out of memory - trying to allocate requested amount (4112 bytes)...
Insufficient memory for GC_all_nils

[QuLogic]

Same for TestTest/X86Linux, though I didn't notice it because most of those are intentional failures.

[aykevl]

Sounds like a QEMU issue (though it's still on us to fix, probably). I think I've seen the same issue when running locally (I'm running Fedora Asahi). We don't test for this in CI, since (almost) all our CI is running amd64 and not 386.