Change preference keys of duplicate settings between
display and battery to avoid duplication in search.
Bug: 33701673
Test: make RunSettingsRoboTests
Change-Id: Iaad52f16ce33c478c64bcec656cc8edbe0c97283
Merged-In: I56c82e9e7f163d345065ca478849de9b14c173fe
By using MasterSwitchPreference, we make "battery saver" to have
two parts: left part is the clickable summary jumping to other
fragment while right part is a switch toggle.
Also remove the previous battery saver preference.
Bug: 34279051
Test: RunSettingsRoboTests
Change-Id: If36fa9741e413a9bbdd57fa67a2c15b6e457afd7