Auto merge of #85869 - tmiasko:box-free, r=nagisa
Auto merge of #85869 - tmiasko:box-free, r=nagisa

Remove special handling of `box_free` from `LocalAnalyzer`

The special casing of `box_free` predates the use of dominators in
analyzer. It is no longer necessary now that analyzer verifies that
the first assignment dominates all uses.

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