Fix expectation for fast/css/font-face-download-error.html on Win7

It seems passing on Win7 now. It looked failing because the expectation
file contained FAILs.
Also removing unnecessary platform-specific expectation files.

BUG=304953

Review URL: https://codereview.chromium.org/26476002

git-svn-id: svn://svn.chromium.org/blink/trunk@159251 bbb929c8-8fbe-4397-9dbb-9b2b20218538