Mark pytorch and chainer tests to be used for continuous testing.

[nadiaya]

Merge Checklist

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• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works (if appropriate)
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[laurenyu]

s/integration/testing in the commit message - these aren't used as part of a build system

[codecov-io]

Codecov Report

Merging #290 into master will increase coverage by 0.06%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #290      +/-   ##
==========================================
+ Coverage   92.42%   92.48%   +0.06%     
==========================================
  Files          49       49              
  Lines        3313     3313              
==========================================
+ Hits         3062     3064       +2     
+ Misses        251      249       -2

Impacted Files	Coverage Δ
src/sagemaker/local/image.py	87.68% <0%> (+0.58%)	⬆️

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