SupplicantHal: Store death recipients

Also, Removed an unused flag from SupplicantStaIface.java.

Bug: 33383725
Test: Unit tests.
Test: Killed wpa_supplicant on the device and ensured the callbacks are
invoked.

Change-Id: I62ec2459ad552bca95c9f9b96032c936c14461fb
2 files changed
tree: 87185932d90a4e80c6523df93b8e30d8b47fb3ae
  1. libwifi_hal/
  2. libwifi_system/
  3. service/
  4. tests/
  5. PREUPLOAD.cfg