Hypothesis' error reporting is broken in IPython (on Windows)

[rsokl]

Introduced in #2313

Context: running a failing test in IPython on Windows, using Hypothesis 5.1.4

WinError123 is raised from pathlib when running a failing Hypothesis test in the IPython console or a notebook:

@given(x=st.booleans())
def test(x):
    assert False

>>> test()

You can add @seed(210798464927815903715427164820480292552) to this test to reproduce this failure.
---------------------------------------------------------------------------
AssertionError                            Traceback (most recent call last)
~\Anaconda3\envs\testing2\lib\site-packages\hypothesis\core.py in _execute_once_for_engine(self, data)
    646         try:
--> 647             result = self.execute_once(data)
    648             if result is not None:

~\Anaconda3\envs\testing2\lib\site-packages\hypothesis\core.py in execute_once(self, data, print_example, is_final, expected_failure)
    601         # In most cases this will delegate straight to `run(data)`.
--> 602         result = self.test_runner(data, run)
    603 

~\Anaconda3\envs\testing2\lib\site-packages\hypothesis\executors.py in default_new_style_executor(data, function)
     51 def default_new_style_executor(data, function):
---> 52     return function(data)
     53 

~\Anaconda3\envs\testing2\lib\site-packages\hypothesis\core.py in run(data)
    597                             report(output.getvalue())
--> 598                         return test(*args, **kwargs)
    599 

<ipython-input-18-f7c304bea5eb> in test_range_length(x)
      3 @given(x=st.booleans())
----> 4 def test_range_length(x):
      5     assert False

~\Anaconda3\envs\testing2\lib\site-packages\hypothesis\core.py in test(*args, **kwargs)
    521                 start = benchmark_time()
--> 522                 result = self.test(*args, **kwargs)
    523                 finish = benchmark_time()

<ipython-input-18-f7c304bea5eb> in test_range_length(x)
      4 def test_range_length(x):
----> 5     assert False
      6 

AssertionError: 

During handling of the above exception, another exception occurred:

OSError                                   Traceback (most recent call last)
<ipython-input-18-f7c304bea5eb> in <module>
      5     assert False
      6 
----> 7 test_range_length()
      8 # </COGINST>

<ipython-input-18-f7c304bea5eb> in test_range_length()
      2 # <COGINST>
      3 @given(x=st.booleans())
----> 4 def test_range_length(x):
      5     assert False
      6 

~\Anaconda3\envs\testing2\lib\site-packages\hypothesis\core.py in wrapped_test(*arguments, **kwargs)
   1078                         get_trimmed_traceback()
   1079                     )
-> 1080                     raise the_error_hypothesis_found
   1081 
   1082         # After having created the decorated test function, we need to copy

~\Anaconda3\envs\testing2\lib\pathlib.py in resolve(self, strict)
   1159         if self._closed:
   1160             self._raise_closed()
-> 1161         s = self._flavour.resolve(self, strict=strict)
   1162         if s is None:
   1163             # No symlink resolution => for consistency, raise an error if

~\Anaconda3\envs\testing2\lib\pathlib.py in resolve(self, path, strict)
    203                 while True:
    204                     try:
--> 205                         s = self._ext_to_normal(_getfinalpathname(s))
    206                     except FileNotFoundError:
    207                         previous_s = s

OSError: [WinError 123] The filename, directory name, or volume label syntax is incorrect: '<ipython-input-18-f7c304bea5eb>'