[Flaky] Flaky Test test_clamp on windows/cpu

[stsukrov]

NDArray Test: Test Failed at C:\jenkins_slave\workspace\ut-julia10-cpu\julia\test\unittest\ndarray.jl:900

  Expression: all(clip_down .<= copy(clipped) .<= clip_up)

Stacktrace:

 [1] test_clamp() at C:\jenkins_slave\workspace\ut-julia10-cpu\julia\test\unittest\ndarray.jl:900

 [2] macro expansion at C:\jenkins_slave\workspace\ut-julia10-cpu\julia\test\unittest\ndarray.jl:1574 [inlined]

 [3] macro expansion at C:\cygwin\home\Administrator\buildbot\worker\package_win64\build\usr\share\julia\stdlib\v1.0\Test\src\Test.jl:1083 [inlined]

 [4] top-level scope at C:\jenkins_slave\workspace\ut-julia10-cpu\julia\test\unittest\ndarray.jl:1557

[ Info: NDArray::clamp!

As seen here:
http://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/mxnet-validation%2Fwindows-cpu/detail/master/523/pipeline/87

[mxnet-label-bot]

Hey, this is the MXNet Label Bot.
Thank you for submitting the issue! I will try and suggest some labels so that the appropriate MXNet community members can help resolve it.
Here are my recommended labels: Test, Flaky

[stsukrov]

@mxnet-label-bot add [Flaky, Test, Windows]

[zachgk]

Another failure at http://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/mxnet-validation%2Fwindows-cpu/detail/PR-14668/4/pipeline

@mxnet-label-bot add [Julia]

[arcadiaphy]

Run through this flaky test several times, it happens on linux too:
http://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/mxnet-validation%2Funix-cpu/detail/PR-14693/4/pipeline/258

[iblislin]

Close via #14776.