test: remove unnecessary chai.use statement

test/Greeter.ts

@@ -1,6 +1,5 @@
-import chai from "chai";
 import { Signer } from "@ethersproject/abstract-signer";
-import { deployContract, solidity } from "ethereum-waffle";
+import { deployContract } from "ethereum-waffle";
 import { ethers } from "@nomiclabs/buidler";
 
 import GreeterArtifact from "../artifacts/Greeter.json";
@@ -8,8 +7,6 @@ import GreeterArtifact from "../artifacts/Greeter.json";
 import { Greeter } from "../typechain/Greeter";
 import { shouldBehaveLikeGreeter } from "./Greeter.behavior";
 
-chai.use(solidity);
-
 setTimeout(async function () {
   const signers: Signer[] = await ethers.getSigners();
   const admin: Signer = signers[0];