By Felix Njini and Clara Denina JOHANNESBURG/LONDON (Reuters) – Anglo American is preparing to freeze spending on growth and widen job cuts in South Africa, going far beyond its initial savings target and paving the way to mothballing some higher-cost platinum mines, sources familiar with the matter said. Anglo’s sweeping spending cuts could be announced as soon as Friday, when the miner updates investors on its three-year outlook, five sources said. The sources said measures include shelving an ambitious plan to boost output at Anglo American Platinum’s key Mogalakwena mine, and, if metals pr…