adding stacktrace in Jenkinsfile_utils.groovy

[access2rohit]

Description

to inspect cause of Python2 failure in CI (Unix CPU)
To identify root cause of : #16995

Upon Inspecting different timeout on Unix CPU in the following runs:
http:https://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/mxnet-validation%2Funix-cpu/detail/PR-16965/12/pipeline/296 Py3 CPU Debug
http:https://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/mxnet-validation%2Funix-cpu/detail/PR-16971/8/pipeline/294 Py2 CPU
http:https://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/mxnet-validation%2Funix-cpu/detail/PR-17018/5/pipeline/294 Py2 CPU
http:https://jenkins.mxnet-ci.amazon-ml.com/blue/organizations/jenkins/mxnet-validation%2Funix-cpu/detail/master/1387/pipeline/47 CPU MKLDNN / CPU_MKLDNN_MKL (build)

http:https://jenkins.mxnet-ci.amazon-ml.com/blue/rest/organizations/jenkins/pipelines/mxnet-validation/pipelines/unix-cpu/branches/PR-16885/runs/9/nodes/294/steps/786/log/?start=0 Py2 CPU
http:https://jenkins.mxnet-ci.amazon-ml.com/blue/rest/organizations/jenkins/pipelines/mxnet-validation/pipelines/unix-cpu/branches/master/runs/1371/nodes/294/steps/747/log/?start=0 Py2 CPU
http:https://jenkins.mxnet-ci.amazon-ml.com/blue/rest/organizations/jenkins/pipelines/mxnet-validation/pipelines/unix-cpu/branches/master/runs/1336/nodes/294/steps/796/log/?start=0 Py2 CPU
http:https://jenkins.mxnet-ci.amazon-ml.com/blue/rest/organizations/jenkins/pipelines/mxnet-validation/pipelines/unix-cpu/branches/master/runs/1337/nodes/294/steps/784/log/?start=0 Py2 CPU

All the tests passed when looked into the logs of Jenkin's run but it fails with message:

End of Pipeline
Timeout has been exceeded
Finished: ABORTED

you can see many files when you grep for Cancelling nested steps due to timeout, but all of them have just one line : caught "Exception name"

This PR prints the stacktrace of the exception to help identify the root cause of CI timeouts in jenkins

Checklist

Essentials

Please feel free to remove inapplicable items for your PR.

• Changes are complete (i.e. I finished coding on this PR)
• To the best of my knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change

[access2rohit]

@anirudh2290 @marcoabreu Can you review ?

[anirudh2290]

were you able to test this somewhere ?

[access2rohit]

No I tested this code in a different file for stacktrace. I don't know how to. Let me know if you do

[anirudh2290]

Apologies, i dont know how it edited your comment .

No I tested this code in a different file for stacktrace. I don't know how to. Let me know if you do

Okay, thats what I was looking for. Testing the line of code if it works in general. To test in this specific code, you can throw an exception from throw block and see if it prints stacktrace in a dev environment.