Revert "kvprober: metamorphically enable / configure kvprober"

This reverts (most of) commit 769ba1c.

That commit metamorphically enabled kvprober. This has been observed to
be destabliziing to unit tests. When the metamorphic constant is
enabled (50% of the time) and when kvprober is fast enough, random
ranges will see extra requests that they aren’t expecting. This adds
nondeterminism which can trip up tests in any number of different ways.

All of the following flakes have been tracked back to kvprober:

Fixes cockroachdb#107864.
Fixes cockroachdb#108242.
Fixes cockroachdb#108441.
Fixes cockroachdb#108349.
Fixes cockroachdb#108124.
Closes cockroachdb#108366.

Release note: None

Author: nvb

pkg/kv/kvprober/BUILD.bazel

@@ -17,7 +17,6 @@ go_library(
         "//pkg/roachpb",
         "//pkg/settings",
         "//pkg/settings/cluster",
-        "//pkg/util",
         "//pkg/util/log",
         "//pkg/util/log/logcrash",
         "//pkg/util/metric",

pkg/kv/kvprober/settings.go

@@ -14,12 +14,9 @@ import (
 	"time"
 
 	"github.com/cockroachdb/cockroach/pkg/settings"
-	"github.com/cockroachdb/cockroach/pkg/util"
 	"github.com/cockroachdb/errors"
 )
 
-var defaultEnabled = util.ConstantWithMetamorphicTestBool("kv.prober.*.enabled", false)
-
 // kv.prober.bypass_admission_control controls whether kvprober's requests
 // should bypass kv layer's admission control. Setting this value to true
 // ensures that kvprober will not be significantly affected if the cluster is
@@ -30,13 +27,14 @@ var bypassAdmissionControl = settings.RegisterBoolSetting(
 	"set to bypass admission control queue for kvprober requests; "+
 		"note that dedicated clusters should have this set as users own capacity planning "+
 		"but serverless clusters should not have this set as SREs own capacity planning",
-	util.ConstantWithMetamorphicTestBool("kv.prober.bypass_admission_control.enabled", true))
+	true,
+)
 
 var readEnabled = settings.RegisterBoolSetting(
 	settings.TenantWritable,
 	"kv.prober.read.enabled",
 	"whether the KV read prober is enabled",
-	defaultEnabled)
+	false)
 
 // TODO(josh): Another option is for the cluster setting to be a QPS target
 // for the cluster as a whole.
@@ -72,7 +70,7 @@ var writeEnabled = settings.RegisterBoolSetting(
 	settings.TenantWritable,
 	"kv.prober.write.enabled",
 	"whether the KV write prober is enabled",
-	defaultEnabled)
+	false)
 
 var writeInterval = settings.RegisterDurationSetting(
 	settings.TenantWritable,
@@ -150,7 +148,7 @@ var quarantineWriteEnabled = settings.RegisterBoolSetting(
 		"quarantine pool holds a separate group of ranges that have previously failed "+
 		"a probe which are continually probed. This helps determine outages for ranges "+
 		" with a high level of confidence",
-	defaultEnabled)
+	false)
 
 var quarantineWriteInterval = settings.RegisterDurationSetting(
 	settings.TenantWritable,