Only use PROCESS_STATE_TOP as foreground time.

There are some miscalculations in state FOREGROUND_SERVICE and
FOREGROUND, so we move them out of the foreground time for now.

We will fix it after O and may add them back later.

Bug: 37000096
Test: RunSettingsRoboTests
Change-Id: Ic3f2f7fa69e8a213895c601630d1cca94fd32220