changefeedccl: disable drain watcher by default

#102717 introduced a mechanism allowing for an orderly shutdown of changefeed
aggregators and an up-to-date frontier information to reduce duplicates during
a node restart in 23.2. However, we've recently identified a bug that could
lead to bad behavior. It's unclear where the bug is yet. This patch disables
this feature by default.

Fixes: #123371
Release note: Disabled a changefeed optimization on reducing duplicates during
aggregator restarts due to its bad performance.

pkg/ccl/changefeedccl/changefeed_processors.go

@@ -137,7 +137,7 @@ var aggregatorEmitsShutdownCheckpoint = settings.RegisterBoolSetting(
 	settings.ApplicationLevel,
 	"changefeed.shutdown_checkpoint.enabled",
 	"upon shutdown aggregator attempts to emit an up-to-date checkpoint",
-	true,
+	false,
 )
 
 type drainWatcher <-chan struct{}

pkg/server/drain.go

@@ -85,7 +85,7 @@ var (
 		"server.shutdown.jobs_wait",
 		"the maximum amount of time a server waits for all currently executing jobs "+
 			"to notice drain request and to perform orderly shutdown",
-		10*time.Second,
+		0,
 		settings.NonNegativeDurationWithMaximum(10*time.Minute),
 		settings.WithName("server.shutdown.jobs.timeout"),
 		settings.WithPublic)