Refactor Drop EtherCat packet test am: 6f6b1a4684

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3158803

Change-Id: I78a850311dbd4fbdb62013d9e868c5fb5862d892
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>