We should collect more precise estimates of execution time. The ScopedTimer currently uses a SystemClockSource which only has millisecond precision generating imprecise and unstable estimates in some cases. Consider replacing the SystemClockSource with the SystemTickSource.

Expected outcome of this ticket:

1. "executionTimeMillisEstimate" in the explain output should be more precise.
2. Introduce an additional field "executionTimeMicrosEstimate" in the explain output for cost calibration use. This new field should be guarded by an internal query knob. It will be added to the explain output only if requested.