Fix CTS-on-GSI: testProcessStatePssValue failures

The PSS sampling of processes is kicked off after certain
amount of time when the process state is stable, and it also
depends on the oom adj updates. Toggling the screen ON/OFF
will result in full oom adj updates and trigger the PSS sampling.

Bug: 147692723
Test: atest CtsStatsdHostTestCases:ProcStatsValidationTests
Change-Id: Iaea92f6c46438f216012f9999642099f5aaa8726