Use DU.getDataMw() ; clean up use of DU.getDataParsoid().

`DU.getDataMw` caches the parsed data.

The `DU.getDataParsoid` tweak was a cleanup requested on an old patch
which almost got lost in my tree.

Change-Id: Ic57a11d5fc0759f2acdc55a1512688932384b3ab