Revert "Use bitmap to maintain which signal is being handled" am: 9d0fc0b43a am: b74df9a0dc am: cb3c552bdd

Original change: https://android-review.googlesource.com/c/platform/art/+/2417614

Change-Id: Ia4f0b9fd5a724841d14484f0721095534e537d52
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>