health-check: Don't remove perl

perl is still used to setup some part of the system, removing it
generates runtime issues. We shall get rid of perl before disabling it.
health: Only test physical sockets not all cores

When testing cpu performance and memory bandwidth, it's much more
faster testing a single core per physical socket.

This is much more scalable when considering the amount of time required
to test a server. Testing all cores doesn't have either a great interest
since they will perform the same as they do run on the same physical
socket.