Partial cherrypick of "CTS: Ensure battery saver will prevent jobs"

On the master branch, the CTS test factored out a skip condition to a
method. We need the refactoring on P as well, so that the addition
necessary for more types of batteryless devices merges cleanly.

Change-Id: I56e8c68c35ea51596e232a16b7e602e5946dd1df
Merged-In: I56e8c68c35ea51596e232a16b7e602e5946dd1df
Bug: 126777005
Test: CtsBatterySavingTestCases
(cherry picked from commit a92f36f32d2ea3cbe8e77b4bb7e378622406c4f1)
3 files changed