Reland "Add a core configuration that disables the zygote."

In targets that do not include a zygote binary, attempting to start the
zygote service will result in repeated service restarts. Avoid this by
providing a way for targets to opt out of declaring a zygote service.

The fvp_mini target does not have a zygote, so apply this opt-out to
that target.

Relanding after fixing breakage on an internal branch.

Bug: 217455793
Change-Id: Ic26f76142afb5f700bd7b12359d62feb2652b617