roachtest: skip kv/quiescence/nodes=3 in prep for deletion

This test is flaky on multiple branches, but the flakes are not actionable.
Rather than adding "the works" (statement bundles, etc), we are going to remove
this test and rely on `kv/gracefuldraining` and (weekly test) `kv/restart`.
Similar functionality is also covered through the perturbation/full/restart
test, though we have issues with the perturbation test harness as well.

This PR only skips the test and is suitable for backporting. A follow-up PR on
master will fully remove the test (and there is no need to backport that).

Closes cockroachdb#156357.
Closes cockroachdb#152052.
Closes cockroachdb#154238.

Epic: none

Author: tbg

pkg/cmd/roachtest/tests/kv.go

@@ -460,6 +460,7 @@ func registerKVContention(r registry.Registry) {
 func registerKVQuiescenceDead(r registry.Registry) {
 	r.Add(registry.TestSpec{
 		Name:                "kv/quiescence/nodes=3",
+		Skip:                "https://github.com/cockroachdb/cockroach/issues/156357",
 		Owner:               registry.OwnerKV,
 		Cluster:             r.MakeClusterSpec(4, spec.WorkloadNode()),
 		CompatibleClouds:    registry.AllExceptAWS,