[io] (NFC) get rid of redundant tests to try passing CI on fedora32 node
[io] (NFC) get rid of redundant tests to try passing CI on fedora32 node

This test suite is failing with "Error: Cannot allocate memory" and I believe
it is because of low ulimit memlock settings on the CI machine. Try and reduce
the number of simultaneous io_urings open at once.

root-mirror/root,root-mirror/root,karies/root,olifre/root,olifre/root,karies/root,root-mirror/root,karies/root,olifre/root,karies/root,olifre/root,karies/root,root-mirror/root,karies/root,root-mirror/root,olifre/root,karies/root,olifre/root,karies/root,olifre/root,root-mirror/root,olifre/root,olifre/root,root-mirror/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,karies/root,root-mirror/root