This commit allows to log tofu detection always, even if the rest of the webfonts library is not loaded. By default this is disabled. To enable it, set the variable $wgULSTofuLoggingChance to a number between 0 and 100, indicating the chance of it getting logged. The idea of the lottery is that even a partial sample can be useful. Change-Id: Ia08fe0de348b7eebfa95498a6be58ae41608ba3b