Test createAddress

Benchmarks gas usage

Note the estimator needs to be updated as this is now variable-gas to the
state.

processor/ethereum/router/contracts/tests/CreateAddress.sol

@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: AGPL-3.0-only
+pragma solidity ^0.8.26;
+
+import "Router.sol";
+
+// Wrap the Router with a contract which exposes the address
+contract CreateAddress is Router {
+  constructor() Router(bytes32(uint256(1))) {}
+
+  function createAddressForSelf(uint256 nonce) external returns (address) {
+    return Router.createAddress(nonce);
+  }
+}