feat: replace the cosmos-db usecases in the tests with core/testing (backport #21525) (#21720)

Co-authored-by: cool-developer <51834436+cool-develope@users.noreply.github.com>
Co-authored-by: Julien Robert <julien@rbrt.fr>

simapp/simd/cmd/root.go

@@ -5,9 +5,9 @@ package cmd
 import (
 	"os"
 
-	dbm "github.com/cosmos/cosmos-db"
 	"github.com/spf13/cobra"
 
+	coretesting "cosmossdk.io/core/testing"
 	"cosmossdk.io/log"
 	"cosmossdk.io/simapp"
 	"cosmossdk.io/simapp/params"
@@ -31,7 +31,7 @@ import (
 func NewRootCmd() *cobra.Command {
 	// we "pre"-instantiate the application for getting the injected/configured encoding configuration
 	// note, this is not necessary when using app wiring, as depinject can be directly used (see root_v2.go)
-	tempApp := simapp.NewSimApp(log.NewNopLogger(), dbm.NewMemDB(), nil, true, simtestutil.NewAppOptionsWithFlagHome(simapp.DefaultNodeHome))
+	tempApp := simapp.NewSimApp(log.NewNopLogger(), coretesting.NewMemDB(), nil, true, simtestutil.NewAppOptionsWithFlagHome(simapp.DefaultNodeHome))
 	encodingConfig := params.EncodingConfig{
 		InterfaceRegistry: tempApp.InterfaceRegistry(),
 		Codec:             tempApp.AppCodec(),