A map iteration was causing a non-deterministic order in output entries. The default behaviour is to preserve the same order of the input zips, which is necessary to ensure a deterministic output for deterministic inputs. Bug: b/322788229 Test: Ran a couple of builds and confirmed no cache misses from the output of merge_zips. Change-Id: I3217e6887ab108d213a290b59da5b33d51b8241f