Revert "Add library definition for test purposes" am: c286f6a494

Original change: https://android-review.googlesource.com/c/platform/external/zopfli/+/2920274

Change-Id: I6c42a12157ffb960f97e7337fcd42aad4d53fe84
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>