Improve NewDatabasePerformanceTests

They didn't properly report timings. It included setup time.
Also cleaned up code and added CREATE TABLE performance test.

Cherry-pick from 66c1852c

Test: run_newdb_perf_test.sh
Bug: 63942513
Bug: 65302651
Merged-In: I15fcb5fa43f81e8ea39c2e29252527a8f3714398
Change-Id: I15fcb5fa43f81e8ea39c2e29252527a8f3714398