Disable PluginTest.GetURL on Mac since it's failing even with retries sometimes.
Disable PluginTest.GetURL on Mac since it's failing even with retries sometimes.

BUG=402164
TBR=avi@chromium.org

Review URL: https://codereview.chromium.org/453153002

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@288448 0039d316-1c4b-4281-b951-d872f2087c98

littlstar/chromium.src,ondra-novak/chromium.src,littlstar/chromium.src,bright-sparks/chromium-spacewalk,bright-sparks/chromium-spacewalk,littlstar/chromium.src,ondra-novak/chromium.src,bright-sparks/chromium-spacewalk,bright-sparks/chromium-spacewalk,bright-sparks/chromium-spacewalk,littlstar/chromium.src,ondra-novak/chromium.src,littlstar/chromium.src,ondra-novak/chromium.src,bright-sparks/chromium-spacewalk,ondra-novak/chromium.src,bright-sparks/chromium-spacewalk,ondra-novak/chromium.src,littlstar/chromium.src,ondra-novak/chromium.src,bright-sparks/chromium-spacewalk,littlstar/chromium.src,littlstar/chromium.src,bright-sparks/chromium-spacewalk,ondra-novak/chromium.src,ondra-novak/chromium.src