kdump:'kexec -c' only supports on rhel8 and fedora rawhide
The 'kexec_load' system call (which load the 2nd kernel) is not supported on RHEL-9 and RHEL-10,discussed with kdump developer and we will skip the test 'kexec -c' for kexec boot and kdump test on cki on rhel9 and rhel10.
RHEL7 also doesn't support "-c" explicitly.
So only run kdump test case kexec-boot and kdump-sysrq-c on RHEL8.
Edited by Bruno Goncalves