Use monotonic system time instead of gettimeofday

Several Codec2 plugins used gettimeofday() to measure durations
which could cause overflows if during an inopportune clock change.
Replace with systemTime().

Bug: 229389483
Test: simple playback
Change-Id: Iefcfd12430763162f40a71d5d04e5fea95564069
14 files changed