[automerger skipped] Changed delta_generator to make use of --max_threads am: 5e369ec30a -s ours

am skip reason: Merged-In I9bae92ee43c21926434ab04563a2b4f0678b73eb with SHA-1 cbe8e633f2 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/update_engine/+/23297422

Change-Id: I989852a9f86f239d8cfac84515a5bf6c68ae5ae0
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>