set_mmtests_numactl wasn't invoked

[ZhangYet]

Found that set_mmtests_numactl wasn't invoked before so that export MMTESTS_NUMA_POLICY="fullbind_single_instance_cpu" didn't work when testing the impact of NUMA policies on redis. So I made some changes.

https://github.com/gormanm/mmtests/pull/20

But I found MMTESTS_NUMACTL in some bench like /shellpack_src/src/iozone/iozone-bench, and I don't know why.