bpo-36593: Fix isinstance check for Mock objects with spec executed under tracing...

bpo-36593: Fix isinstance check for Mock objects with spec executed under tracing (GH-12790)

In Python having a trace function in effect while mock is imported causes isinstance to be wrong for MagicMocks. This is due to the usage of super() in some class methods, as this sets the __class__ attribute. To avoid this, as a workaround, alias the usage of super .