Revert "storage: enable the merge queue by default"

This reverts commit 98ca1d0. The merge
queue will be reenabled once flaky tests are fixed.

docs/generated/settings/settings.html

@@ -31,7 +31,7 @@
 <tr><td><code>kv.raft_log.synchronize</code></td><td>boolean</td><td><code>true</code></td><td>set to true to synchronize on Raft log writes to persistent storage ('false' risks data loss)</td></tr>
 <tr><td><code>kv.range.backpressure_range_size_multiplier</code></td><td>float</td><td><code>2</code></td><td>multiple of range_max_bytes that a range is allowed to grow to without splitting before writes to that range are blocked, or 0 to disable</td></tr>
 <tr><td><code>kv.range_descriptor_cache.size</code></td><td>integer</td><td><code>1000000</code></td><td>maximum number of entries in the range descriptor and leaseholder caches</td></tr>
-<tr><td><code>kv.range_merge.queue_enabled</code></td><td>boolean</td><td><code>true</code></td><td>whether the automatic merge queue is enabled</td></tr>
+<tr><td><code>kv.range_merge.queue_enabled</code></td><td>boolean</td><td><code>false</code></td><td>whether the automatic merge queue is enabled</td></tr>
 <tr><td><code>kv.rangefeed.enabled</code></td><td>boolean</td><td><code>false</code></td><td>if set, rangefeed registration is enabled</td></tr>
 <tr><td><code>kv.snapshot_rebalance.max_rate</code></td><td>byte size</td><td><code>2.0 MiB</code></td><td>the rate limit (bytes/sec) to use for rebalance snapshots</td></tr>
 <tr><td><code>kv.snapshot_recovery.max_rate</code></td><td>byte size</td><td><code>8.0 MiB</code></td><td>the rate limit (bytes/sec) to use for recovery snapshots</td></tr>

pkg/storage/merge_queue.go

@@ -49,7 +49,7 @@ const (
 var MergeQueueEnabled = settings.RegisterBoolSetting(
 	"kv.range_merge.queue_enabled",
 	"whether the automatic merge queue is enabled",
-	true,
+	false,
 )
 
 // MergeQueueInterval is a setting that controls how often the merge queue waits