exception jump should not cross mrb_funcall border; close #276

src/vm.c

@@ -1013,6 +1013,10 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
         while (ci[0].ridx == ci[-1].ridx) {
           cipop(mrb);
           ci = mrb->ci;
+	  if (ci->acc < 0) {
+	    mrb->jmp = prev_jmp;
+	    longjmp(*(jmp_buf*)mrb->jmp, 1);
+	  }
 	  while (eidx > mrb->ci->eidx) {
 	    ecall(mrb, --eidx);
 	  }