kvserver: fix TestCheckConsistencyInconsistent's VFS use

Fix TestCheckConsistencyInconsistent to not access an Engine's filesystem after
closing the Engine. Instead, acquire a vfs.FS directly from the sticky VFS
registry and use that to check for the inconsistency death rattle.

Resolves #110293.
Epic: none
Release note: none

pkg/kv/kvserver/consistency_queue_test.go

@@ -337,6 +337,7 @@ func TestCheckConsistencyInconsistent(t *testing.T) {
 
 	// Write some arbitrary data only to store on n2. Inconsistent key "e"!
 	s2 := tc.GetFirstStoreFromServer(t, 1)
+	s2AuxDir := s2.TODOEngine().GetAuxiliaryDir()
 	var val roachpb.Value
 	val.SetInt(42)
 	// Put an inconsistent key "e" to s2, and have s1 and s3 still agree.
@@ -411,9 +412,10 @@ func TestCheckConsistencyInconsistent(t *testing.T) {
 	assert.Equal(t, hashes[0], hashes[2])    // s1 and s3 agree
 	assert.NotEqual(t, hashes[0], hashes[1]) // s2 diverged
 
-	// A death rattle should have been written on s2.
-	eng := s2.TODOEngine()
-	f, err := eng.Open(base.PreventedStartupFile(eng.GetAuxiliaryDir()))
+	// A death rattle should have been written on s2. Note that the VFSes are
+	// zero-indexed whereas store IDs are one-indexed.
+	fs := stickyVFSRegistry.Get("1")
+	f, err := fs.Open(base.PreventedStartupFile(s2AuxDir))
 	require.NoError(t, err)
 	b, err := io.ReadAll(f)
 	require.NoError(t, err)