statedb: return correct validator code size (#4475)

The function `state_object.CodeSize` erroneously returns the validator
code size to be 0. This functionality is only used by the EVM, where the
size is overridden by the `ValidatorCodeFixEpoch` hard fork to be 0
anyway.

However, for nodes currently syncing blocks before the hard fork was
effective, this causes an error. A transaction which attempts to mint an
NFT to a validator address prior to the hard fork would have failed,
because `onERC1155Received` is not implemented by a validator's code.
With the erroneous line, the transaction goes through - causing
a node with the unpatched binary to reject the block.

core/state/state_object.go

@@ -561,7 +561,7 @@ func (s *Object) CodeSize(db Database) int {
 	if s.validatorWrapper || err != nil {
 		vcSize, errVCSize := db.ValidatorCodeSize(s.addrHash, common.BytesToHash(s.CodeHash()))
 		if errVCSize == nil && vcSize > 0 {
-			return size
+			return vcSize
 		}
 		if s.validatorWrapper {
 			s.setError(fmt.Errorf("can't load validator code size %x for account address hash %x : %v", s.CodeHash(), s.addrHash, err))