MediaSyncTest: increase ramp up time due to initial latency in AudioTrack.

This was a cherry-pick of 224b704de06c7e84752c39090ac587a45e6da346
Bug: 26962365

(cherry-picked from 2dde480f97ee77437046825b6d2ca9287251226e)

Change-Id: I17803f000f866564a6afca68681e950267959b89
1 file changed