HTMLSelectElement remove should only accept an index

http://www.whatwg.org/specs/web-apps/current-work/multipage/the-button-element.html#the-select-element

Our IDL file had a case for remove(HTMLOptionElement) but it never
worked so our behavior was really matching the spec as well as Firefox
and IE. This removes the method from our IDL file as well as the
actual implementation.

Tests passes before and after this patch in Blink.
It passes in Firefox 30
IE11 throws exceptions for out of range indexes but otherwise behaves
the same

BUG=345697

Review URL: https://codereview.chromium.org/175473002

git-svn-id: svn://svn.chromium.org/blink/trunk@167614 bbb929c8-8fbe-4397-9dbb-9b2b20218538