Disable more tests on Mac Valgrind.

BUG=247601
TBR=benwells@chromium.org

Review URL: https://codereview.chromium.org/137983011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247207 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247207