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

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

Change-Id: I8b691bdf11df22cc15b0e21d368697033f9420c9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>