Remove GSNv1 contracts (#2521)

Co-authored-by: Francisco Giordano <frangio.1@gmail.com>

test/helpers/set-gsn-provider.js

@@ -1,15 +0,0 @@
-const { GSNDevProvider } = require('@openzeppelin/gsn-provider');
-
-function setGSNProvider (Contract, accounts) {
-  const baseProvider = Contract.currentProvider;
-  Contract.setProvider(
-    new GSNDevProvider(baseProvider, {
-      txfee: 70,
-      useGSN: false,
-      ownerAddress: accounts[8],
-      relayerAddress: accounts[9],
-    }),
-  );
-};
-
-module.exports = { setGSNProvider };