Reduce BatteryConstraintTest flakiness.

Battery updates would sometimes happen after the test ran the adb shell
command, meaning that JobScheduler got a battery update with a higher
sequence number than what the test expected. Higher sequence numbers
should be fine since that means the adb set value should have been
processed.

Bug: 138253466
Test: atest android.jobscheduler.cts.BatteryConstraintTest
Change-Id: I3baaa1b85c2f8a16b5bf06ca735fac6cbc0054fd