Delete paint invalidaiton code in RenderLayerModelObject::styleWillChange.

This code should not be necessary, these cases are handled by the mainline
repaint-after-layout machinery.

BUG=391036

Review URL: https://codereview.chromium.org/360193002

git-svn-id: svn://svn.chromium.org/blink/trunk@177431 bbb929c8-8fbe-4397-9dbb-9b2b20218538