Add check for optimize after each mutation operation.

Optimize is an important job for AppSearch to work properly.
It could collect garbage and release resources. Without it, the garbage
resource will last forever and the device's space will be fulled up by
zombie documents.

The algorithm to trigger optimize is:
1: Query garbage resource info after a batch of mutation operations.
2: Only trigger optimize if there are enough resource could be released.

The behavior exists in AppSearch Jetpack for a while and working properly
for our Jetpack dogfooders.

Bug: 175255572
Test: FrameworkOptimizeStrategyTest
Test: AppSearchConfigTest
Test: AppSearchImplTest
Change-Id: Ib7ae475cc035d1b69969df1e22ac409895e0e3fa