debuggerd now notifies the Activity Manager about native crashes

The Activity Manager sets up a permission-guarded domain socket, which
debuggerd connects to when a crash happens.  If this is successful,
the daemon then mirrors the logged crash report to that socket, then
closes it.

The Activity Manager parses the native crash dump supplied by debuggerd
and forwards it to the standard app-crashed code.  The UX result is
that users now see the normal "app has stopped unexpectedly" dialog
with "report" and "okay" options for native crashes, not just for
DVM-mediated crashes.

Bug 8322568

Change-Id: Ie1b279896c603bd74d82d6cfcfd66a8f231da134