Add ERC7739 and ERC7739Utils (#5664)

test/utils/cryptography/ERC7739.test.js

@@ -0,0 +1,13 @@
+const { ethers } = require('hardhat');
+const { shouldBehaveLikeERC1271 } = require('./ERC1271.behavior');
+
+describe('ERC7739', function () {
+  describe('for an ECDSA signer', function () {
+    before(async function () {
+      this.signer = ethers.Wallet.createRandom();
+      this.mock = await ethers.deployContract('ERC7739ECDSAMock', [this.signer.address]);
+    });
+
+    shouldBehaveLikeERC1271({ erc7739: true });
+  });
+});