HTML repr benchmarks failing on Travis

[TomAugspurger]

e.g. https://dev.azure.com/pandas-dev/pandas/_build/results?buildId=7904

2019-02-04T18:50:51.0110372Z [ 11.57%] ··· frame_methods.Repr.time_html_repr_trunc_mi                  failed
2019-02-04T18:50:51.0110695Z [ 11.57%] ···· Traceback (most recent call last):
2019-02-04T18:50:51.0111142Z                  File "/home/vsts/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/asv/benchmark.py", line 1039, in main_run_server
2019-02-04T18:50:51.0111204Z                    main_run(run_args)
2019-02-04T18:50:51.0111455Z                  File "/home/vsts/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/asv/benchmark.py", line 913, in main_run
2019-02-04T18:50:51.0111504Z                    result = benchmark.do_run()
2019-02-04T18:50:51.0111753Z                  File "/home/vsts/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/asv/benchmark.py", line 412, in do_run
2019-02-04T18:50:51.0111802Z                    return self.run(*self._current_params)
2019-02-04T18:50:51.0112042Z                  File "/home/vsts/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/asv/benchmark.py", line 506, in run
2019-02-04T18:50:51.0112105Z                    min_run_count=self.min_run_count)
2019-02-04T18:50:51.0112359Z                  File "/home/vsts/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/asv/benchmark.py", line 569, in benchmark_timing
2019-02-04T18:50:51.0112421Z                    timing = timer.timeit(number)
2019-02-04T18:50:51.0112648Z                  File "/home/vsts/miniconda3/envs/pandas-dev/lib/python3.7/timeit.py", line 176, in timeit
2019-02-04T18:50:51.0112695Z                    timing = self.inner(it, self.timer)
2019-02-04T18:50:51.0112884Z                  File "<timeit-src>", line 6, in inner
2019-02-04T18:50:51.0112934Z                  File "/home/vsts/work/1/s/asv_bench/benchmarks/frame_methods.py", line 226, in time_html_repr_trunc_mi
2019-02-04T18:50:51.0112977Z                    self.df3._repr_html_()
2019-02-04T18:50:51.0113024Z                  File "/home/vsts/work/1/s/pandas/core/frame.py", line 651, in _repr_html_
2019-02-04T18:50:51.0113065Z                    import IPython
2019-02-04T18:50:51.0113320Z                  File "/home/vsts/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/IPython/__init__.py", line 55, in <module>
2019-02-04T18:50:51.0113382Z                    from .terminal.embed import embed
2019-02-04T18:50:51.0113634Z                  File "/home/vsts/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/IPython/terminal/embed.py", line 16, in <module>
2019-02-04T18:50:51.0113686Z                    from IPython.terminal.interactiveshell import TerminalInteractiveShell
2019-02-04T18:50:51.0113952Z                  File "/home/vsts/miniconda3/envs/pandas-dev/lib/python3.7/site-packages/IPython/terminal/interactiveshell.py", line 81, in <module>
2019-02-04T18:50:51.0114176Z                    if not _stream or not hasattr(_stream, 'isatty') or not _stream.isatty():
2019-02-04T18:50:51.0114223Z                ValueError: I/O operation on closed file