DOM: Make moveBefore() throw for all pre-move validity checks

This CL makes moveBefore() match the spec PR [1], with regard to the
agreed-upon error-throwing behavior for all pre-moving validity and
hierarchy conditions. This means throwing an exception for:
 - Disconnected parent destination or move target
 - Cross-document Nodes
 - Destination parent that is not an Element node
 - Move target that is not an Element or character data

[1]: whatwg/dom#1307

R=nrosenthal@chromium.org

Bug: 40150299
Change-Id: Iaf5243fb2762e21ede068a222600bd158859fe92