expand_cpulist() interpolated the untrusted cpu_spec argument directly
into a python3 -c source string, letting a crafted spec break out of
the string literal and execute arbitrary Python. Pass it through the
CPU_SPEC environment variable instead.

isolation_monitor.sh created its log directory at a predictable
/tmp/isolation_monitor_$$ path with a plain mkdir, which is subject to
a pre-creation symlink attack. Use mktemp -d for an unpredictable,
owner-only directory. Also fix a stale sched_audit.sh reference in the
usage header left over from a prior rename.

Signed-off-by: Wesierski, Dawid <dawid.wesierski@intel.com>