Add ID to native events.

To separate this big work into pieces I introduced a placeholder in
InputTransport used to initialize native input events received from
InputFlinger until InputFlinger can generate random sequence numbers.

The work in InputDispatcher wires up ID between events and notify args
as well.

Bug: 144889238
Test: Builds and some smoke tests.
Test: atest libinput_tests
Change-Id: I1ef7f243cc89a8b6e07ba9ba30a43c21eedb16ce
Merged-In: I1ef7f243cc89a8b6e07ba9ba30a43c21eedb16ce
(cherry picked from commit 4cc839fe)