chore(jest): halve the max workers (#3017)

jest.config.js

@@ -0,0 +1,11 @@
+module.exports = /** @type {import('@jest/types').Config.InitialOptions} */ ({
+  // all of our tests have a browser and a node process, so the default max workers is too many.
+  maxWorkers: Math.ceil(require('os').cpus().length / 2),
+  rootDir: './test',
+  testEnvironment: './jest',
+  testMatch:  ['**/?(*.)jest.[jt]s'],
+  testRunner: 'jest-circus/runner',
+  testTimeout: 10000,
+  globalSetup: './jest/setup.js',
+  globalTeardown: './jest/teardown.js'
+});

jest.config.json

@@ -1,9 +0,0 @@
-{
-  "rootDir": "./test",
-  "testEnvironment": "./jest",
-  "testMatch":  ["**/?(*.)jest.[jt]s"],
-  "testRunner": "jest-circus/runner",
-  "testTimeout": 10000,
-  "globalSetup": "./jest/setup.js",
-  "globalTeardown": "./jest/teardown.js"
-}