This is because the version of unzip on osx doesn't support zip64, so it can't
unzip large repositories like blink.

BUG=261741

Review URL: https://codereview.chromium.org/251413002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@266151 0039d316-1c4b-4281-b951-d872f2087c98