Add ScrapeAndCompare utility

[bwplotka]

See kubernetes/kubernetes#108277

Ideally we have method for comparing expected output with HTTP scrape, or at least body response form scrape.

Optionally:

• We could also learn from utils https://github.com/kubernetes/component-base/blob/master/metrics/testutil/testutil.go#L48 and add some of them to client_golang

cc @kakkoyun @saswatamcode

[stale]

Hello 👋 Looks like there was no activity on this issue for the last 3 months. Do you mind updating us on the status? Is this still reproducible or needed? If yes, just comment on this PR or push a commit. Thanks! 🤗
If there will be no activity in the next 4 weeks, this issue will be closed (we can always reopen an issue if we need!).

[sazary]

@bwplotka i think we can resolve this now

[stale]

Hello 👋 Looks like there was no activity on this issue for the last 3 months. Do you mind updating us on the status? Is this still reproducible or needed? If yes, just comment on this PR or push a commit. Thanks! 🤗
If there will be no activity in the next 4 weeks, this issue will be closed (we can always reopen an issue if we need!).

[stale]

Closing for now as promised, let us know if you need this to be reopened! 🤗