Skip RootInlineBox size check on windows for now

Skip the RootInlineBox size check in RootInlineBox.cpp for now until we
can figure out why it fails on 64bit windows builds.

TBR=scottmg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/345853002

git-svn-id: svn://svn.chromium.org/blink/trunk@176570 bbb929c8-8fbe-4397-9dbb-9b2b20218538