Added updateEngine_downloadAction_fuzzer am: 55fec45931 am: b0bda4937f

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/1810483

Change-Id: I31aef428cf4b374e1abc6ee79a2e60972f70aa5f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>