Fix incorrect assert for cgroup file system type

[omajid]

From mono/mono#21280 (comment):

This is what coreCLR does for the same check:

   struct statfs stats;
   int result = statfs("/sys/fs/cgroup", &stats);
   if (result != 0)
           return 0;

   switch (stats.f_type)
   {
       case TMPFS_MAGIC: return 1;
       case CGROUP2_SUPER_MAGIC: return 2;
       default:
           assert(!"Unexpected file system type for /sys/fs/cgroup");
           return 0;
   }

We both bail if result is not zero from the statfs call. If the f_type not one of the two values I am interested in I just write the message and proceed. It appears coreCLR would abort due to the assert. Should we worry about any message and just proceed with the cgroup checks simply returning false and using the normal system values? It would appear coreCLR is getting a non-zero result as you aren't seeing assertions/aborts when running this with coreCLR. Is something actually mounted at /sys/fs/cgroup when running in your chroot?

We should fix this assert (which just happens to become a no-op at Release builds) to correctly handle environments in which cgroups are not enabled, specially chroots.

cc @akoeplinger @janvorli @tmds

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[akoeplinger]

This isn't mono-specific, moving to area-PAL-coreclr