[YUNIKORN-2184] Fix goconst linter issues

[targetoee]

What is this PR for?

This PR focus on fix linter issues about goconst warning. Some const are set for better reuse.

What type of PR is it?

• - Bug Fix
• - Improvement
• - Feature
• - Documentation
• - Hot Fix
• - Refactoring

Todos

This PR only fixes the parts which are pointed out by the linter.
While in application_test.go, the naming of variable names doesn't have a unified format.
It would be better to reformat that, and one way to achieve this is by setting common variables in util_test.go and reuse them.

What is the Jira issue?

YUNIKORN-2184

How should this be tested?

It's been test using ./tools/golanci-lint run ./... | grep goconst to checkout all the goconst waring are fixed.

Screenshots (if appropriate)

N/A

Questions:

N/A

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (afbb4a8) 69.46% compared to head (dad41eb) 69.46%.
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #736   +/-   ##
=======================================
  Coverage   69.46%   69.46%           
=======================================
  Files          50       50           
  Lines        7993     7993           
=======================================
  Hits         5552     5552           
  Misses       2252     2252           
  Partials      189      189           

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[FrankYang0529]

+1. Thank you