WebGL conformance test expectations update

Windows failures
  conformance_ogles_GL_atan_atan_001_to_008
  conformance_ogles_GL_atan_atan_009_to_012
  conformance_ogles_GL_control_flow_control_flow_001_to_008

BUG=322794,322795
TEST=
TBR=bajones@chromium.org,kbr@chromium.org

Review URL: https://codereview.chromium.org/83953004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236898 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236898