Remove RenderObject::checkForPaintInvalidation()

It was used during layout to avoid unnecessary local invalidations.
However, with RACUN we set flag instead of issuing invalidation during
layout, making the local invalidation optimization unnecessary.

Also the name is confusing with shouldCheckForPaintInvalidation().

Review URL: https://codereview.chromium.org/647903002

git-svn-id: svn://svn.chromium.org/blink/trunk@183679 bbb929c8-8fbe-4397-9dbb-9b2b20218538