Problem when using custom cmap key to recall older command-line from history

vimrc
```
cmap <A-j> <DOWN>
cmap <A-k> <UP>
```

test input - 1
```
:echo '111'<CR>
:echo '222'<CR>
:<UP><UP><CR> ---> (will echo '111')
:<UP> --> (will see last command "echo '111'")
```

test input - 1
```
:echo '111'<CR>
:echo '222'<CR>
:<A-k><A-k><CR> ---> (will echo '111')
:<A-k> --> (will see last command "echo '222'" ?!)
```
