Finding an <object> element by name only works it has no children other than <param> elements

Finding an <object> element by name only works it has no children other than <param> elements.
We used to do this to match a very old behavior of IE:
https://bugs.webkit.org/show_bug.cgi?id=5449

However, both IE10 and FF24 do not have this restriction anymore.

This patch updates our behavior to match IE and FF's, meaning that an <object> element can
be found by name even if it has children that are not <param> elements.

R=eseidel
BUG=313292

Review URL: https://codereview.chromium.org/50453004

git-svn-id: svn://svn.chromium.org/blink/trunk@160990 bbb929c8-8fbe-4397-9dbb-9b2b20218538