Remove some unnecessary operations

- LaunchActivityItem already always copies all parameters.
  The Configuration doesn't need to copy twice.

- Except freeze screen is no longer used, configChanges=0 for
  startFreezingScreenLocked is always no-op.

Bug: 163976519
Test: CtsWindowManagerDeviceActivity
Change-Id: I57e335f94129badd7688b85df667f0ffd3243ede