util: improve unicode support

The array grouping function relies on the width of the characters.
It was not calculated correct so far, since it used the string
length instead.
This improves the unicode output by calculating the mono-spaced
font width (other fonts might differ).

PR-URL: https://github.com/nodejs/node/pull/31319


Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Steven R Loomis <srloomis@us.ibm.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Minwoo Jung <nodecorelab@gmail.com>