mrb_run to return last evaluated value

src/codegen.c

@@ -523,7 +523,7 @@ scope_body(codegen_scope *s, node *tree)
   int idx = scope->idx;
 
   if (!s->iseq) {
-    codegen(scope, tree->cdr, NOVAL);
+    codegen(scope, tree->cdr, VAL);
     genop(scope, MKOP_A(OP_STOP, 0));
   }
   else {

src/vm.c

@@ -1558,7 +1558,7 @@ mrb_run(mrb_state *mrb, struct RProc *proc, mrb_value self)
       /*        stop VM */
     L_STOP:
       mrb->jmp = prev_jmp;
-      return mrb_nil_value();
+      return regs[irep->nlocals];
     }
 
     CASE(OP_ERR) {