message: [XLA] Add IsTiled() function to HloSharding.
diff: @@ -150,6 +150,10 @@ class HloSharding {
  [](const HloSharding& s) { return s.IsManual(); });
  }
  + // Returns weather the sharding represents a tiled sharding where the mapping
  + // between devices and tiles is represented through 'tile_assignment()'.
  + bool IsTiled() const { return !IsTileMaximal() && !IsManual(); }
  +
  // Returns if the sharding has partial replication and partial sharding. If
  // true, data is sharded according to other dimensions of tile_assignment(),
  // but replicated across devices along the last dimension.
  