Exclude ProxyScriptFetcherImplTest.NoCache from Dr. Memory

TBR=zhaoqin@chromium.org
BUG=327695

Review URL: https://codereview.chromium.org/111973005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@240111 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 240111