[WIP] many: cgroupsv2 spread run

[bboozzoo]

Only check how far can spread tests go.

[bboozzoo]

Some of the patches in the branch are in master already. Let's see what fails after a merge from master.

[zyga]

@bboozzoo can you please rebase this and perhaps propose parts separately.

There are some new SELinux denials:

+ ausearch -i -m AVC --checkpoint /home/gopath/src/github.com/snapcore/snapd/tests/runtime-state/audit-stamp --start checkpoint
----
type=AVC msg=audit(09/20/19 08:32:48.864:933) : avc:  denied  { relabelto } for  pid=13222 comm=unsquashfs name=snap.yaml dev="sda1" ino=8205 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.864:934) : avc:  denied  { setattr } for  pid=13222 comm=unsquashfs name=snap.yaml dev="sda1" ino=8205 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.864:935) : avc:  denied  { relabelto } for  pid=13222 comm=unsquashfs name=meta dev="sda1" ino=8204 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.864:936) : avc:  denied  { setattr } for  pid=13222 comm=unsquashfs name=meta dev="sda1" ino=8204 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.865:937) : avc:  denied  { search } for  pid=12945 comm=snapd name=unpack dev="sda1" ino=8203 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.865:938) : avc:  denied  { read } for  pid=12945 comm=snapd name=snap.yaml dev="sda1" ino=8205 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.865:939) : avc:  denied  { open } for  pid=12945 comm=snapd path=/tmp/read-file901211458/unpack/meta/snap.yaml dev="sda1" ino=8205 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.865:940) : avc:  denied  { getattr } for  pid=12945 comm=snapd path=/tmp/read-file901211458/unpack/meta/snap.yaml dev="sda1" ino=8205 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.865:941) : avc:  denied  { getattr } for  pid=12945 comm=snapd path=/tmp/read-file901211458/unpack dev="sda1" ino=8203 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.866:942) : avc:  denied  { read } for  pid=12945 comm=snapd name=unpack dev="sda1" ino=8203 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.866:943) : avc:  denied  { open } for  pid=12945 comm=snapd path=/tmp/read-file901211458/unpack dev="sda1" ino=8203 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.866:944) : avc:  denied  { write } for  pid=12945 comm=snapd name=unpack dev="sda1" ino=8203 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.866:945) : avc:  denied  { remove_name } for  pid=12945 comm=snapd name=snap.yaml dev="sda1" ino=8205 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.866:946) : avc:  denied  { unlink } for  pid=12945 comm=snapd name=snap.yaml dev="sda1" ino=8205 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=file permissive=1 
----
type=AVC msg=audit(09/20/19 08:32:48.866:947) : avc:  denied  { rmdir } for  pid=12945 comm=snapd name=meta dev="sda1" ino=8204 scontext=system_u:system_r:snappy_t:s0 tcontext=system_u:object_r:unlabeled_t:s0 tclass=dir permissive=1 

[bboozzoo]

#7702 adds Fedora 31 to spread system. Since F31 already defaults to unified hierarchy, there is no need for this PR anymore.