feat: add unstable API for dynamic program loading

web3.js/test/connection.test.js

@@ -1,10 +1,12 @@
 // @flow
 
-import {Account} from '../src/account';
-import {Connection} from '../src/connection';
-import {SystemProgram} from '../src/system-program';
+import {
+  Account,
+  Connection,
+  SystemProgram,
+} from '../src';
 import {mockRpc, mockRpcEnabled} from './__mocks__/node-fetch';
-import {url} from './url.js';
+import {url} from './url';
 
 if (!mockRpcEnabled) {
   // The default of 5 seconds is too slow for live testing sometimes