performance: fix critical bugs

the call to ActivityManager.isLowRamDeviceStatic() is not available
on every device.
my custom sdk exposed it to android studio, thats why i didn't notice it.

replace the call with a more safe one, also check if current device is
running kitkat, otherwise the call will crash too.

Change-Id: I3f0e981308619ea520e2f777bc10aeb57e9c20bc