Added a flag to DOM-fragment unpacking to update fragment DSR

* This patch adds a flag to DOM fragment unpacking to update
  fragment DSR in cases where the fragment needs it (references
  block + reused template/extension/images content). In other
  cases of dom-fragment use, the DSR should not be updated.

  Ex: All cases where fragments are used to implement parsing
  scopes (all A-tag content currently) since DSR computation
  is set up with offsets in the top-level source.

  This is not just an optimization, but a correctness issue
  since the fragment unwrapper always sets the fragment DSR
  on the first node which would be incorrect in scenarios where
  the fragment DOM has multiple top-level nodes.

* Parser test runs now have better DSR values in certain cases.

Change-Id: If1f5bf98dab246a3c8a1869b38335e90268cb5c5
Merge "Added a flag to DOM-fragment unpacking to update fragment DSR"