Skip writing message field in an atom if it's empty

Test: unit test added
Bug: 120635548
Change-Id: I825b1ce526944a20fe65705508ad180ece37492c
Merged-In: I825b1ce526944a20fe65705508ad180ece37492c
(cherry picked from commit c930868f50c532b2c8ff9d82e0a5c2bb3f3e924d)
3 files changed
tree: 77251839321f6c48811aac9dd0ae2c8d00fae15d
  1. bin/