FIX: test_no_et hanging on Python 3.8

[effigies]

Summary

Travis is consistently hanging on Python 3.8, apparently at test_no_et. This adds verbosity, and splits up the test to hopefully make it easier to track down.

Cannot reproduce this locally by running the specific file, but there may be state changes in the test workers...

List of changes proposed in this PR (pull-request)

Acknowledgment

• (Mandatory) I acknowledge that this contribution will be available under the Apache 2 license.

[codecov]

Codecov Report

Merging #3239 into maint/1.5.x will increase coverage by 0.03%.
The diff coverage is 87.50%.

@@               Coverage Diff               @@
##           maint/1.5.x    #3239      +/-   ##
===============================================
+ Coverage        64.96%   64.99%   +0.03%     
===============================================
  Files              302      302              
  Lines            39929    39942      +13     
  Branches          5279     5282       +3     
===============================================
+ Hits             25939    25962      +23     
+ Misses           12925    12919       -6     
+ Partials          1065     1061       -4     

Flag	Coverage Δ
#unittests	64.99% <87.50%> (+0.03%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
nipype/interfaces/io.py	56.41% <ø> (ø)
nipype/interfaces/ants/utils.py	88.94% <86.66%> (-0.33%)	⬇️
nipype/conftest.py	96.15% <100.00%> (+0.15%)	⬆️
nipype/algorithms/misc.py	45.12% <0.00%> (-0.12%)	⬇️
nipype/pipeline/plugins/base.py	59.72% <0.00%> (+1.64%)	⬆️
nipype/pipeline/plugins/legacymultiproc.py	69.11% <0.00%> (+3.43%)	⬆️

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[effigies]

Unclear why this fixed the hanging, but I guess at least we can get through tests.