Unpin deps when unnecessary

contracts/extensions/test/order_validator.ts

@@ -1,5 +1,12 @@
-import { ERC20Wrapper, ERC721Wrapper } from '@0x/contracts-asset-proxy';
-import { ExchangeWrapper } from '@0x/contracts-exchange';
+import {
+    DummyERC20TokenContract,
+    DummyERC721TokenContract,
+    ERC20ProxyContract,
+    ERC20Wrapper,
+    ERC721ProxyContract,
+    ERC721Wrapper,
+} from '@0x/contracts-asset-proxy';
+import { ExchangeContract, ExchangeWrapper } from '@0x/contracts-exchange';
 import {
     chaiSetup,
     constants,
@@ -16,15 +23,7 @@ import { BigNumber } from '@0x/utils';
 import * as chai from 'chai';
 import * as _ from 'lodash';
 
-import {
-    artifacts,
-    DummyERC20TokenContract,
-    DummyERC721TokenContract,
-    ERC20ProxyContract,
-    ERC721ProxyContract,
-    ExchangeContract,
-    OrderValidatorContract,
-} from '../src';
+import { artifacts, OrderValidatorContract } from '../src';
 
 chaiSetup.configure();
 const expect = chai.expect;