Add test for getOffsetFrom(Element|Text)Node

Assert the result at every offset in the DOM.

Change-Id: I5a8ca28a7ee22c49d23077ad6993499ec726bbb3
Fix getOffsetFrom(Element|Text)Node for annotated aliens

* Replace addOuterLength with a recursionDirection as we only
  want to add length when the first recursion was to the left,
  and add nothing if we recursed to the right.
* Use isContentEditable which is the proper calculated boolean.
  contentEditable is often just (string)'inherit' :/
  Mercifully this works in in IE.
* Only check for the IE ce bug if we aren't recursing at all.

Bug: 53766
Change-Id: I247d1b68484cb510335b5f6789269ec254376cfe
Merge changes I247d1b68,I5a8ca28a

* changes:
  Fix getOffsetFrom(Element|Text)Node for annotated aliens
  Add test for getOffsetFrom(Element|Text)Node