Issue 19769 shows that if __main__ in a package throws ImportError, runpy will incorrectly report the package as not being directly executable (when it actually claims to be executable, it's just broken)

This can be fixed in 3.3+ by checking for an appropriate value in the name attribute of the caught exception, and only wrapping it if the failed lookup was for the __main__ submodule we're looking for.

The associated test can just use a __main__.py that deliberately raises ImportError.