Feature/bunny hop (#2647)

* `@0x/contracts-erc20-bridge-sampler`: Add TwoHopSampler + refactor

* `@0x/asset-swapper`: Refactor + add two-hop skeleton

* Round out two-hop support in asset-swapper

* Add BalancerSampler, use it for two-hop quotes

* Fix bugs discovered from simbot

* rebases are hard

* Add intermediate token to MultiHop source breakdown

* Fix market buy bugs

* Use hybrid on-chain/off-chain sampling for Balancer

* Another day, another rebase

* Update changelogs

* Address PR feedback, CI fixes

* Address more PR feedback

contracts/integrations/test/framework/actors/maker.ts

@@ -97,7 +97,7 @@ export function MakerMixin<TBase extends Constructor>(Base: TBase): TBase & Cons
             const [makerToken, makerFeeToken, takerToken, takerFeeToken] = Pseudorandom.sampleSize(
                 this.actor.deployment.tokens.erc20,
                 4, // tslint:disable-line:custom-no-magic-numbers
-            );
+            )!;
 
             // Maker and taker set balances/allowances to guarantee that the fill succeeds.
             // Amounts are chosen to be within each actor's balance (divided by 8, in case
@@ -146,7 +146,7 @@ export function MakerMixin<TBase extends Constructor>(Base: TBase): TBase & Cons
             const [leftMakerToken, leftTakerToken, makerFeeToken, takerFeeToken] = Pseudorandom.sampleSize(
                 this.actor.deployment.tokens.erc20,
                 4, // tslint:disable-line:custom-no-magic-numbers
-            );
+            )!;
             const rightMakerToken = leftTakerToken;
             const rightTakerToken = leftMakerToken;