autopkgtest fails in hirsute on s390x

[Balint Reczey]

https://autopkgtest.ubuntu.com/packages/r/ruby-http/hirsute/s390x

Triggered with hello only:
https://objectstorage.prodstack4-5.canonical.com/v1/AUTH_77e2ada1e7a84929a74ba3b87153c0ac/autopkgtest-hirsute/hirsute/s390x/r/ruby-http/20201216_224705_0e275@/log.gz
...
autopkgtest: WARNING: package ruby-http is not installed though it should be
autopkgtest: WARNING: Test dependencies are unsatisfiable with using apt pinning. Retrying with using all packages from hirsute-proposed
Reading package lists...
Building dependency tree...
Reading state information...
Correcting dependencies...Starting pkgProblemResolver with broken count: 1
Starting 2 pkgProblemResolver with broken count: 1
Investigating (0) autopkgtest-satdep:s390x < 0 @iU mK Nb Ib >
Broken autopkgtest-satdep:s390x Depends on ruby-http:s390x < none @un H >
  Considering ruby-http:s390x 1 as a solution to autopkgtest-satdep:s390x -2
  Removing autopkgtest-satdep:s390x rather than change ruby-http:s390x
Done
 Done
Starting pkgProblemResolver with broken count: 0
Starting 2 pkgProblemResolver with broken count: 0
Done
...

The reason is ruby-http-parser:s390x build missing, but this does not prevent ruby-http:all autopkgtest to be executed.