Remove some MIUI code in NetworkPolicyManagerService to support new NetworkAssistant mobile limit logic.

MIUI-30602

Change-Id: Ifc4af5e150acc375551e30fd269fe674d62cedba
Signed-off-by: mochangming <mochangming@xiaomi.com>
kill system application's backgroud process started by broadcast for more memory

MIUI-28628

Change-Id: I2c62135be39af16fe5bf86e4bbed8eebb14d41b8
Signed-off-by: mochangming <mochangming@xiaomi.com>

Conflicts:

	services.jar.out/smali/com/android/server/am/BroadcastQueue.smali
modify low memory notification style

Ref-Id: I6e7e89726d04ce963d2dece3f2ab24b2ee8fc2d9
Change-Id: I683f7cb7cad903217b78264a1bd309883313587d
Signed-off-by: mochangming <mochangming@xiaomi.com>

Conflicts:

	services.jar.out/smali/com/android/server/DeviceStorageMonitorService.smali