Remove fixed seed for test_loss/test_operator_gpu.test_triplet_loss

[haojin2]

Description

Fix for #11703

Checklist

Essentials

• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage:
• Unit tests are added for small changes to verify correctness (e.g. adding a new operator)
• Nightly tests are added for complicated/long-running ones (e.g. changing distributed kvstore)
• Build tests will be added for build configuration changes (e.g. adding a new build option with NCCL)
• Code is well-documented:
• For user-facing API changes, API doc string has been updated.
• For new C++ functions in header files, their functionalities and arguments are documented.
• For new examples, README.md is added to explain the what the example does, the source of the dataset, expected performance on test set and reference to the original paper if applicable
• Check the API doc at http://mxnet-ci-doc.s3-accelerate.dualstack.amazonaws.com/PR-$PR_ID/$BUILD_ID/index.html
• To the my best knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change

Changes

• Remove fixed seed for test_loss/test_operator_gpu.test_triplet_loss

Comments

Passed 10000 times on both CPU & GPU:

python tools/flakiness_checker.py test_loss.test_triplet_loss -n 10000
INFO:root:No test seed provided, using random seed
/home/ubuntu/anaconda3/lib/python3.6/site-packages/urllib3/contrib/pyopenssl.py:46: DeprecationWarning: OpenSSL.rand is deprecated - you should use os.urandom instead
  import OpenSSL.SSL
/home/ubuntu/anaconda3/lib/python3.6/site-packages/nose/util.py:453: DeprecationWarning: inspect.getargspec() is deprecated, use inspect.signature() or inspect.getfullargspec()
  inspect.getargspec(func)
[INFO] Setting module np/mx/python random seeds, use MXNET_MODULE_SEED=2074824000 to reproduce.
test_loss.test_triplet_loss ... ok

----------------------------------------------------------------------
Ran 1 test in 16726.734s

OK

python tools/flakiness_checker.py test_operator_gpu.test_triplet_loss -n 10000
INFO:root:Testing: /home/ubuntu/incubator-mxnet/tests/python/gpu/test_operator_gpu.py:test_triplet_loss
INFO:root:No test seed provided, using random seed
/home/ubuntu/anaconda3/lib/python3.6/site-packages/urllib3/contrib/pyopenssl.py:46: DeprecationWarning: OpenSSL.rand is deprecated - you should use os.urandom instead
  import OpenSSL.SSL
/home/ubuntu/anaconda3/lib/python3.6/site-packages/nose/util.py:453: DeprecationWarning: inspect.getargspec() is deprecated, use inspect.signature() or inspect.getfullargspec()
  inspect.getargspec(func)
[INFO] Setting module np/mx/python random seeds, use MXNET_MODULE_SEED=1944359470 to reproduce.
test_operator_gpu.test_triplet_loss ... ok

----------------------------------------------------------------------
Ran 1 test in 13768.859s

OK

[haojin2]

@marcoabreu