Performance tuning for contact aggregator2

1. Skip already aggregated raw contacts during aggregation algorithm upgrade.
2. Remove case conversion during email comparion for better performance.
3. Fix bugs in the ContactAggregatorHelper to fix the flaky unit test.

Bug:21466686
Bug:19908937
Change-Id: I6f59894a4fdc605fe1b92ac82e2ac9e90561a158
7 files changed