Suppress data races in Quic and disk_cache_test_util

TBR=rtenneti@chromium.org
BUG=313733,313726

Review URL: https://codereview.chromium.org/54673004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232134 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232134