@0x/contracts-staking: Import randomAddress() instead of defining our own.

contracts/staking/test/unit_tests/delegator_reward_test.ts

@@ -7,6 +7,7 @@ import {
     hexRandom,
     hexSlice,
     Numberish,
+    randomAddress,
 } from '@0x/contracts-test-utils';
 import { BigNumber } from '@0x/utils';
 import { LogEntry } from 'ethereum-types';
@@ -230,10 +231,6 @@ blockchainTests.resets('delegator unit rewards', env => {
         };
     }
 
-    function randomAddress(): string {
-        return hexRandom(constants.ADDRESS_LENGTH);
-    }
-
     function computeDelegatorRewards(
         totalRewards: Numberish,
         delegatorStake: Numberish,