op-chain-ops: sanity check not empty bytecode

Sanity check that empty bytecode is not set in the state
for the `Proxy`. There are other checks for this after
the migration happens and this never should happen so this
is just a sanity check to catch a problem earlier in the process.

op-chain-ops/genesis/setters.go

 package genesis
 
 import (
+	"errors"
 	"fmt"
 	"math/big"
 
@@ -109,6 +110,9 @@ func setProxies(db vm.StateDB, proxyAdminAddr common.Address, namespace *big.Int
 	if err != nil {
 		return err
 	}
+	if len(depBytecode) == 0 {
+		return errors.New("Proxy has empty bytecode")
+	}
 
 	for i := uint64(0); i <= count; i++ {
 		bigAddr := new(big.Int).Or(namespace, new(big.Int).SetUint64(i))