Issue #15715: Ignore failed imports triggered by the use of fromlist. When the fromlist argument is specified for __import__() and the attribute doesn't already exist, an import is attempted. If that fails (e.g. module doesn't exist), the ImportError will now be silenced (for backwards-compatibility). This *does not* affect ``from ... import ...`` statements. Thanks to Eric Snow for the patch and Simon Feltman for reporting the regression.