Refactor core/pod tests

[tenzen-y]

What this PR does / why we need it:
I refactored core/pod tests to remove test_job dependencies.

Which issue(s) this PR fixes (optional, in Fixes #<issue number>, #<issue number>, ... format, will close the issue(s) when PR gets merged):
Part-of #1816

Checklist:

• Docs included if any changes are user facing

[coveralls]

Pull Request Test Coverage Report for Build 5917653729

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.01%) to 42.777%

---

Files with Coverage Reduction	New Missed Lines	%
pkg/controller.v1/mpi/mpijob.go	1	91.06%

Totals
Change from base Build 5852486416:	-0.01%
Covered Lines:	3737
Relevant Lines:	8736

---

💛 - Coveralls

[johnugeorge]

@tenzen-y Thanks for this. There are other files that uses test job. Is it planned as a separate PR?

[tenzen-y]

@tenzen-y Thanks for this. There are other files that uses test job. Is it planned as a separate PR?

Yes, I will work on other files at separate PRs because we need to refactor the whole of pod_control.

[johnugeorge]

/lgtm
/approve

[google-oss-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: johnugeorge, tenzen-y

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