Disable flaky test test_operator.test_dropout (v1.3.x)

[lebeg]

Description

Disable flaky test test_operator.test_dropout which is failing on the v.1.3.x branch:

http://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/incubator-mxnet/detail/v1.3.x/97/pipeline

======================================================================
FAIL: test_operator.test_dropout
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Anaconda3\envs\py3\lib\site-packages\nose\case.py", line 197, in runTest
    self.test(*self.arg)
  File "C:\jenkins_slave\workspace\ut-python-gpu\tests\python\unittest\common.py", line 173, in test_new
    orig_test(*args, **kwargs)
  File "C:\jenkins_slave\workspace\ut-python-gpu\tests\python\unittest\test_operator.py", line 5853, in test_dropout
    check_dropout_ratio(0.0, shape)
  File "C:\jenkins_slave\workspace\ut-python-gpu\tests\python\unittest\test_operator.py", line 5797, in check_dropout_ratio
    assert exe.outputs[0].asnumpy().min() == min_value
AssertionError: 
-------------------- >> begin captured logging << --------------------
common: INFO: Setting test np/mx/python random seeds, use MXNET_TEST_SEED=428273587 to reproduce.
--------------------- >> end captured logging << ---------------------

Issue tracked here: #12329

Checklist

Essentials

Please feel free to remove inapplicable items for your PR.

• The PR title starts with [MXNET-$JIRA_ID], where $JIRA_ID refers to the relevant JIRA issue created (except PRs with tiny changes)
• Changes are complete (i.e. I finished coding on this PR)
• All changes have test coverage:
• Unit tests are added for small changes to verify correctness (e.g. adding a new operator)
• Nightly tests are added for complicated/long-running ones (e.g. changing distributed kvstore)
• Build tests will be added for build configuration changes (e.g. adding a new build option with NCCL)
• Code is well-documented:
• For user-facing API changes, API doc string has been updated.
• For new C++ functions in header files, their functionalities and arguments are documented.
• For new examples, README.md is added to explain the what the example does, the source of the dataset, expected performance on test set and reference to the original paper if applicable
• Check the API doc at http://mxnet-ci-doc.s3-accelerate.dualstack.amazonaws.com/PR-$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

• Feature1, tests, (and when applicable, API doc)
• Feature2, tests, (and when applicable, API doc)

Comments

• If this change is a backward incompatible change, why must this change be made.
• Interesting edge cases to note here

[lebeg]

@nswamy @szha

[anirudhacharya]

@mxnet-label-bot add [pr-awaiting-review]

[nswamy]

This has more than flaky tests failing, you are also updating submodules? I don't want to bring submodules updates to the branch. Please note this expands the scope of the release.

[lebeg]

@nswamy Sorry, you're right. Submodule changes got in by mistake.

[nswamy]

merging as the test that failed is unrelated to this PR.