Flaky cpp test: dropout gpu perf

[eric-haibin-lin]

The dropout cpp test fails intermittently on MXNet master. I can reproduce the failure by running the cpp test locally a couple of times.

Reference failure log:
http://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/mxnet-validation%2Funix-gpu/detail/PR-14066/5/pipeline/

[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

[piyushghai]

@mxnet-label-bot Add [Test, Flaky]

[wkcn]

There is another issue about dropout gpu perf.
http://jenkins.mxnet-ci.amazon-ml.com/job/mxnet-validation/job/unix-gpu/job/PR-14278/1/display/redirect

C++ exception with description "[07:12:07] /work/mxnet/src/resource.cc:429: Check failed: state_space->ctx.dev_id == stream->dev_id (0 vs. -1) The device id of cudnn dropout state space doesn't match that from stream.

Maybe we should modify the code of tests/cpp/include/test_op.h.
opContext_.run_ctx.stream = mshadow::NewStream<gpu>(true, true); -> opContext_.run_ctx.stream = mshadow::NewStream<gpu>(true, true, 0);

[eric-haibin-lin]

I see. Maybe that will fix the the failure reported previously

[eric-haibin-lin]

#14278 fixes the stream used in the test. feel free to reopen if this issue happens again