Add query fuzz test for PRW2

[SungJin1212]

With the introduction of PRW2, we need to ensure that the new ingestion pipeline does not introduce any query results inconsistency compared to the stable PRW1 pipeline.
This PR adds a TestRW1vsRW2QueryFuzz e2e test that verifies that the query results for PRW1 and PRW2 are identical.

Which issue(s) this PR fixes:
Fixes #

Checklist

• Tests updated
• Documentation added
• CHANGELOG.md updated - the order of entries should be [CHANGE], [FEATURE], [ENHANCEMENT], [BUGFIX]

[friedrichg]

small nit

[friedrichg]

Suggested change

	rnd := rand.New(rand.NewSource(seed))
	rnd := rand.New(rand.NewSource(seed))
	ctx := context.Background()
	waitUntilReady(t, ctx, c1, c2, `{job="test"}`, start, end)

This is to ensure we get all series before testing

[yeya24]

Not sure I got why we need a query fuzz test specifically for RWv2...
The fuzz tests are already flaky so I don't know if it helps capture issues or just add more noise.

I think we can have a test for RWv1 vs RWv2 but no need to have any query involved. Simple vector selector should be fine.

[SungJin1212]

@yeya24
Since we already have a compatibility test between PRW1 and Prometheus (TestPrometheusCompatibilityQueryFuzz), evaluating PRW2 against PRW1 can test the compatibility between PRW2 and Prometheus.
Also, it can help when developing PRW2 natively later, in that it validates PRW1 vs PRW2 continuously.
That's right... I'm worried about a noise from the flaky test..