Rename supportsLayoutStateCachedOffsets to supportsPaintInvalidationStateCachedOffsets

We no longer have a concept of cached offsets in LayoutState.
Rename the method to reflect this

R=jchaffraix@chromium.org

Review URL: https://codereview.chromium.org/429863008

git-svn-id: svn://svn.chromium.org/blink/trunk@179661 bbb929c8-8fbe-4397-9dbb-9b2b20218538