This was introduced in 3ca0eb1136102ff01bcc171f53c106326fa4445b, due to an incorrect implementation of `__dir__` (fixed in the previous commit).

It was never released, so this is not a breaking change.

In that commit, `from numpy import *` would reset all the builtins to their defaults, and set `unicode = str`, `long = int`.

Previously this would fail, but only on python 3.7+
```
np.new_member = 1
assert 'new_member' in dir(np)
```

While this isn't something we support anyway, it certainly wasn't intentional.

[ci skip]

Also finish the TODO about figuring out which np.lib.<submodule>'s
are public.

This is a giant mess ...

Before this fix, a reference such as `numpy.wxyz` produced an
incorrect error message because of the invalid format specifiers
in the error message string:

    >>> import numpy
    >>> numpy.wxyz
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/.../numpy/__init__.py", line 206, in __getattr__
        "module %s has no attribute $s".format(__name__, attr))
    AttributeError: module %s has no attribute $s

After the fix:

    >>> import numpy
    >>> numpy.wxyz
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "/.../numpy/__init__.py", line 206, in __getattr__
        "{!r}".format(__name__, attr))
    AttributeError: module 'numpy' has no attribute 'wxyz'

On new python versions, the module level `__getattr__` can be used to import testing and
Tester only when needed (at no speed cost, except for the first time import). Since most users
never use testing, this avoids an expensive import.

getlimits previously called numpy code before all of numpy was loaded,
which often causes circular import issues. This delays getlimits init.

Fixes #12063

Attempts to use this on either cpython27 or cpython35, in either a shell or a script, gives:

    NameError: name '__path__' is not defined

Perhaps I'm calling it wrong, but it might just be broken.