Fix nascent timer never get removed

By design, the nascent timer will be removed after a network
satisfied first request. However, this never happens.
Because the mInactive is false when that happens, so isNascent
is never true.

Furthermore, when removing a nascent timer, the inactivity
state can never be updated since no condition in the
updateInactivityState will be met to update the state correctly.

Thus, update inactive state accordingly when adding/removing the
nascent timer.

Test: TH
Bug: 184227264
Merged-In: I3c2563d4ae4e3715d0c6270344ba8f7ef067872f
Merged-In: I4c1521b6e0ef68ac489771a2ab6b09ef3e381577
Change-Id: I4c1521b6e0ef68ac489771a2ab6b09ef3e381577
  (cherry-picked from ag/14060609)
2 files changed