Remove PersistableBundle(Bundle) usage from ConnectivityService

Because the constuctor PersistableBundle(Bundle) is a hidden
API which is not visible to connectivity mainline module.
Currently, EVENT_NETWORK_TESTED and EVENT_DATA_STALL_SUSPECTED
are two events sent by ConnectivityService so they can build a
PersistableBundle directly and send PersistableBundle instead of
setting Bundle in the data field of the Message.

For EVENT_NETWORK_TESTED, add a new PersistableBundle member in
ConnectivityReportEvent so that the PersistableBundle can be
passed with ConnectivityReportEvent.

For EVENT_DATA_STALL_SUSPECTED, create a Pair<Long, PersistableBundle>
and put this in .obj of the Message, then the PersistableBundle can be
sent with timestampMillis together.

Bug: 177865050
Test: FrameworksNetTests
Change-Id: Ia2220f33f000e7c9439d97617cc08014dc4478a3