This is a backport of Core PR17634 [2/2]
https://github.com/bitcoin/bitcoin/pull/17634/commits/98fbd1cdffaa69357091cc67e959ac21119dfa16
Depends on D8281
The header algorithm is needed in cuckoocache.h for std::find (see PR18565). I'm not sure how Core got away with removing it for multiple months, for us it cause a compiler error.