fix flappy integration test

[mialinx]

Small maps (of 2 items) are randomized badly,
i.e. their keys has the same order almost always, but not always.
This leads to rare test failures in commands that depends on keys order,
such as untag (untag-all-03)

A Pull Request should be associated with an Issue.

We wish to have discussions in Issues. A single issue may be targeted by multiple PRs.
If you're offering a new feature or fixing anything, we'd like to know beforehand in Issues,
and potentially we'll be able to point development in a particular direction.

Related issue: https://github.com/github/orchestrator/issues/0123456789

Thank you! We are open to PRs, but please understand if for technical reasons we are unable to accept each and any PR

Description

This PR [briefly explain what is does]

In case this PR introduced Go code changes:

• contributed code is using same conventions as original code
• code is formatted via gofmt (please avoid goimports)
• code is built via ./build.sh
• code is tested via go test ./go/...

[shlomi-noach]

Thank you. I wonder if this shouldn't be the other way around: that the tests sort the results, and we keep randomized iteration in GetInstanceKeys(). I don't feel strongly either way.

[mialinx]

If you don't rely on any particular order of GetInstanceKeys(), then this patch breaks nothing.

If you do rely on alphabetic order of GetInstanceKeys() (as it looks like in expected_output files and go/inst/tag_dao.go:Untag queries), then there is a bug and this patch fixes it.