Revert "Don't ignore data-parsoid in DOMDiff"

Caused https://bugzilla.wikimedia.org/show_bug.cgi?id=48018.

This reverts commit 2c45ade9723ea06f538ff5b2255dcb5d1fbbd601

Change-Id: Ice057ed419f504ad057a104b12d8e43c4e872e0c