HACK: Don't merge adjacent annotations from Parsoid

Adjacent annotations should not be merged if they both
originate from Parsoid. This is a hack because this logic
should be in Parsoid, not VE.

Bug: 49873
Change-Id: If1e23e3039178300d72b1c0c585931417bb603b5
Merge "HACK: Don't merge adjacent annotations from Parsoid"