Make Range.detach() a no-op

Make Range.detach() a no-op as per DOM4:
http://dom.spec.whatwg.org/#dom-range-detach

This makes the code a lot simpler, as it avoids a lot of null checks and
exception throwing. Also add a UseCounter and a deprecation message to see
if this can be removed entirely from the specification.

Firefox already does this since version 15:
https://bugzilla.mozilla.org/show_bug.cgi?id=702948

However, detach() is not a no-op in IE11.

R=arv@chromium.org, tkent@chromium.org
BUG=367322
TEST=fast/dom/Range/detach-no-op.html

Review URL: https://codereview.chromium.org/252783002

git-svn-id: svn://svn.chromium.org/blink/trunk@173010 bbb929c8-8fbe-4397-9dbb-9b2b20218538