Fix the exitcode when send the atest_exit_event am: b2e1bf3366

Original change: https://android-review.googlesource.com/c/platform/tools/asuite/+/3439862

Change-Id: Ie42b7d158af55d0876190d8ae1cc555acbb1abf3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>