fix prompt and abort with the boot evaluator

fix prompt and abort with the boot evaluator

* libguile/control.h:
* libguile/control.c (scm_i_prompt_pop_abort_args_x): Take a VM instead
  of a prompt, given that it's the VM's registers that record the abort
  arguments, not the prompt registers (which actually point right below
  the abort values).

* libguile/eval.c (eval):
* libguile/throw.c (pre_init_catch): Pass the vm instead of a prompt.