util.isArray() was the sole util.is* type-checking method left over from #52744. The remainder are all EOL as of v23.0.0.

It looks like the motivation for leaving this at the time was to allow for its use to be removed from the form-data library, which it has since been.

Is there another motivation for leaving this as-is, or can it now be made EOL?

cc: @marco-ippolito