storage: disable metamorphism of excises and EFOS

The new excise operation and eventually file-only snapshot (EFOS) features in
Pebble are experimental. Within the 23.2 release, these features must only be
enabled within the context of the disaggregated storage techncial preview.
These features are still experimental and unstable.

Remove the metamorphism of these settings in tests in order to stabilize the
23.2 release branch. As we appraoch release, we want our test failures to be
high signal, and failures dependent on these settings should not block the
release. On the master branch these settings will be enabled unconditionally
soon, and we'll get plenty of test coverage before their general availability
in 24.1.

Epic: none
Informs cockroachdb#112221.
Informs cockroachdb#113973.
Informs cockroachdb#114056.
Release note: none

pkg/storage/pebble.go

@@ -109,8 +109,7 @@ var UseEFOS = settings.RegisterBoolSetting(
 	settings.SystemOnly,
 	"storage.experimental.eventually_file_only_snapshots.enabled",
 	"set to true to use eventually-file-only-snapshots even when kv.snapshot_receiver.excise.enabled is false",
-	util.ConstantWithMetamorphicTestBool(
-		"storage.experimental.eventually_file_only_snapshots.enabled", false), /* defaultValue */
+	false, /* defaultValue */
 	settings.WithPublic)
 
 // UseExciseForSnapshots controls whether virtual-sstable-based excises should
@@ -122,9 +121,8 @@ var UseEFOS = settings.RegisterBoolSetting(
 var UseExciseForSnapshots = settings.RegisterBoolSetting(
 	settings.SystemOnly,
 	"kv.snapshot_receiver.excise.enabled",
-	"set to true to use excises instead of range deletions for KV snapshots",
-	util.ConstantWithMetamorphicTestBool(
-		"kv.snapshot_receiver.excise.enabled", false), /* defaultValue */
+	"set to true to use the experimental and unstable excise operation instead of range deletions for KV snapshots",
+	false, /* defaultValue */
 	settings.WithPublic,
 )