roachtest: fix gossip/restart tests

This patch fixes `acceptance/gossip/restart` and `gossip/restart` by
waiting for all nodes to report ready before restarting nodes, and
unskips them.

Epic: none
Release note: None

pkg/cmd/roachtest/tests/acceptance.go

@@ -31,7 +31,7 @@ func registerAcceptance(r registry.Registry) {
 		registry.OwnerKV: {
 			{name: "decommission-self", fn: runDecommissionSelf},
 			{name: "event-log", fn: runEventLog},
-			{name: "gossip/peerings", fn: runGossipPeerings, skip: "flaky test. tracked in #96091"},
+			{name: "gossip/peerings", fn: runGossipPeerings},
 			{name: "gossip/restart", fn: runGossipRestart},
 			{
 				name:              "gossip/restart-node-one",

pkg/cmd/roachtest/tests/gossip.go

@@ -285,6 +285,7 @@ func runGossipPeerings(ctx context.Context, t test.Test, c cluster.Cluster) {
 	deadline := timeutil.Now().Add(time.Minute)
 
 	for i := 1; timeutil.Now().Before(deadline); i++ {
+		WaitForReady(ctx, t, c, c.All())
 		if err := g.check(ctx, c, g.hasPeers(c.Spec().NodeCount)); err != nil {
 			t.Fatal(err)
 		}
@@ -308,8 +309,6 @@ func runGossipPeerings(ctx context.Context, t test.Test, c cluster.Cluster) {
 }
 
 func runGossipRestart(ctx context.Context, t test.Test, c cluster.Cluster) {
-	t.Skip("skipping flaky acceptance/gossip/restart", "https://github.com/cockroachdb/cockroach/issues/48423")
-
 	c.Put(ctx, t.Cockroach(), "./cockroach")
 	c.Start(ctx, t.L(), option.DefaultStartOpts(), install.MakeClusterSettings())
 
@@ -322,6 +321,7 @@ func runGossipRestart(ctx context.Context, t test.Test, c cluster.Cluster) {
 	deadline := timeutil.Now().Add(time.Minute)
 
 	for i := 1; timeutil.Now().Before(deadline); i++ {
+		WaitForReady(ctx, t, c, c.All())
 		g.checkConnectedAndFunctional(ctx, t, c)
 		t.L().Printf("%d: OK\n", i)