improve the incorrectly written io_uring checks
    
    I wrote certain io_uring checks incorrectly, because I misunderstood
    the comments in the RHEL-11792 ticket. They should be correct now.
    
    In order to properly test the io_uring feature, the feature needs to
    be enabled (it is by default on Fedora). If the kernel command line
    does not contain the "io_uring" string, the automated test adds the
    necessary options and reboots the machine.