Revert "Add cpu-{node,mem,disk} to the testenv JSON"

This reverts commit ddc4284d68290e3fe2318c2a5951696fb6cc3833.

devtest has moved onto full node definitions and these variables will
not be referenced.

Change-Id: I0b9247a981884958f8264ada605470c7834832c7
Merge "Revert "Add cpu-{node,mem,disk} to the testenv JSON""