Col width is not honored when dynamically updated and it would not make table narrower

Increasing the table width by increasing the colgroup width was working
but decreasing the table width by decreasing the colgroup width is not working.

When colgroup width is defined table cell should adjust according to that.
On decreasing colgroup width the cells maxPreferredLogicalWidth was
still set to the earlier value. Setting the setPreferredLogicalWidthsDirty
to true so that cells pref width is calculated again.

I already landed this patch on webkit. Just modified the layout test file and fixed build errors.
http://trac.webkit.org/changeset/162334.

R=jchaffraix@chromium.org
BUG=340252

Review URL: https://codereview.chromium.org/151993004

git-svn-id: svn://svn.chromium.org/blink/trunk@168908 bbb929c8-8fbe-4397-9dbb-9b2b20218538