Disable PPAPINaClGLibcTest.Graphics2D_FlushOffscreenUpdate on Windows

BUG=320548
R=raymes
TBR=raymes

Review URL: https://codereview.chromium.org/59703009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@235683 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 235683