spec2000 expects binaries to be optimised for particular cores and uses
Device's core_names to figure out which cores the benchmark should run
on.
There is one special case, which is "generic", which is not optimised
for a particular uarch. cpumask for this was resolved the same way,
failing the lookup, resulting in the invalid mask 0x0.
To fix this, "generic" is now handled by specifying the mask for all
available CPUs.
Commands have been updated to use the busybox executable that
is installed via WA rather than relying on it already being in
PATH on the device as this would fail for devices that it was
not installed on.
list_or_* functions (e.g. list_or_string) will now always return a list,
however will accept lists or indivitual values. Also added a list_or()
generator function, similar to what already exists for list_of().
