Fix list-style-position: inside

We currently handle list-style-position: inside incorrectly and in
trying to fix this in the past broke handling of it for floating items
(r151263). This change reversed that incorrect fix and instead updated
RenderListItem to invalidate the preferred width for the containing
block once the render tree has been updated to include to marker for
list-style-position: inside list markers.

BUG=278115
TEST=LayoutTests/fast/lists/list-style-position-inside.html
R=leviw@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23601027

git-svn-id: svn://svn.chromium.org/blink/trunk@157560 bbb929c8-8fbe-4397-9dbb-9b2b20218538