[NPM]Make order of iptables entries in UT determinisitc in case of MultipleLabelsToMultipleLabels

[JungukCho]

Reason for Change:

TestAllowMultiplePodSelectors has a flake UT result due to the ordering of ipset in Specs since the order of all ipset values in Specs is not guaranteed in MultiplePodSelectors case.
Thus, in this UT, before checking the iptables entries, sorting Specs is necessary before comparing them.

You can break this UT with this script without this PR.

max=1000
idx=0
while [[ $idx -ne $max ]]
do
/usr/local/go/bin/go test -timeout 30s -v --count=1 -run ^TestAllowMultiplePodSelectors$ github.com/Azure/azure-container-networking/npm
if [[ $? -ne 0 ]]
then
	exit
fi

idx=$((idx+1))
echo $idx
done

Issue Fixed:

Requirements:

• uses conventional commit messages
• includes documentation
• adds unit tests

Notes:
While we have one UT to be sorted in current UTs, we need to generalize this approach in all tests to avoid undeterministic behavior in the added UTs in the future. In addition, I feel like we need to clean up translatePolicy_test.go since it is unnecessarily too lengthy.

[vakalapa]

lgtm

[JungukCho]

There is another issue in this PR (sorted one can cause incorrect results as well). I will update the issue in details and codes according to the issue.

The issue of previous commit is to sort all strings in specs of ipentries. So, if translation function returns incorrect values, they are sorted and possible to be match with expected values.
For example, if translation function returns "azure-npm-a src azure-npm-b dst" with incorrect logics, it will be equal to expected value "azure-npm-a dst azure-npm-b src" after sorting returned and expected values. This is incorrect behavior.
So, it needs to tie a direction with ipset, and then compare the values against expected values.

Note: before merging it, I need to check "expectedLists" values to see whether they have the same issues or not.

"There is another issue in this PR (sorted one can cause incorrect results as well). I will update the issue in details and codes according to the issue."

[JungukCho]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[vakalapa]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 2 pipeline(s).

[JungukCho]

Close now. I am working on fixing this issue in another PR (refactoring translatePolicy.go) which fundamentally fixes this issue while there are reusable commits here. I will revisit them in the other PR.