Rollup merge of #79777 - tmiasko:remove-first-merge, r=lcnr
Rollup merge of #79777 - tmiasko:remove-first-merge, r=lcnr

Remove `first_merge` from liveness debug logs

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