Halve test erofs image size^2 am: bc185040f3 am: ea5aeb2cdc

Original change: https://android-review.googlesource.com/c/platform/system/update_engine/+/2236834

Change-Id: Ic852f6662c106be8d84f76cd673b8ff940e9cd63
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>