tests: added STEP descriptions to new MTU related checks
tests: added STEP descriptions to new MTU related checks

davidvossel/kubevirt,kubevirt/kubevirt,kubevirt/kubevirt,rmohr/kubevirt,stu-gott/kubevirt,kubevirt/kubevirt,stu-gott/kubevirt,kubevirt/kubevirt,davidvossel/kubevirt,stu-gott/kubevirt,stu-gott/kubevirt,rmohr/kubevirt,davidvossel/kubevirt,davidvossel/kubevirt