Add extra delays to service restarts in case of low memory pressure

When the system is on low memory pressure, service restarts could make
the performance worse. Now addinng extra delays in this case; while
when the memory pressure drops, the delays will be decreased too.

BYPASS_INCLUSIVE_LANGUAGE_REASON=legacy API name

Bug: 170309420
Test: atest FrameworksServicesTests:ServiceRestarterTest
Test: atest FrameworksMockingServicesTests:ActiveServicesTest
Change-Id: Ic55276775950316bde199ab017916e8efbee7a73