Auto merge of #5534 - phansch:remove-util-dev, r=flip1995
Auto merge of #5534 - phansch:remove-util-dev, r=flip1995

Remove util/dev script

`cargo dev` has been the replacement for a while, so I think we can
remove it now.

cc #5394

changelog: none

aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust