chore: make no-unused-vars eslint rule error (#5598)

Author: SimenB

.eslintrc.js

@@ -132,6 +132,7 @@ module.exports = {
     // https://github.com/benmosher/eslint-plugin-import/issues/645
     'import/order': 0,
     'no-console': 0,
+    'no-unused-vars': 2,
     'prettier/prettier': [
       2,
       {

packages/jest-cli/src/search_source.js

@@ -12,7 +12,6 @@ import type {Glob, GlobalConfig, Path} from 'types/Config';
 import type {Test} from 'types/TestRunner';
 import type {ChangedFilesPromise} from 'types/ChangedFiles';
 
-import fs from 'fs';
 import path from 'path';
 import micromatch from 'micromatch';
 import DependencyResolver from 'jest-resolve-dependencies';