Merge CR#2716173 & CR#2719986

QC has updated these 2 CRs after we merged them at ag/12009347:
 - CR#2716173: Use Qtimer to improve ElapsedRealTimeNanos accuracy
 - CR#2719986: The callbacks could be stale in GnssMeasurement

Bug: 159768476

Test: Ensure VtsHalGnssV2.0/2.1 are all PASS

CRs-fixed: 2716173
CRs-fixed: 2719986
Change-Id: Ic441a7bcde5ab918d406328f81351a47ac9f1d65
8 files changed