gh-137477: Fix inspect.getblock() for generator expressions (GH-137488)
This fixes also inspect.getsourcelines() and inspect.getsource().
(cherry picked from commit eae9d7de1c)
Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
* Setting the __module__ attribute for a class now removes the
__firstlineno__ item from the type's dict.
* The _collections_abc and _pydecimal modules now completely replace the
collections.abc and decimal modules after importing them. This
allows to get the source of classes and functions defined in these
modules.
* inspect.findsource() now checks whether the first line number for a
class is out of bound.
