test: make test fails when jest force-stops a worker (closes #711)

When a test leaves a timer running, jest force-stops that worker, prints
a warning, and the run still passes. Jest has no option that fails the
run instead. Both test scripts in package.json now run jest through
script/lib/jest.js. It passes jest's output through and exits 1 when
jest printed that warning.

Model: opus-5-5

package.json

@@ -6,8 +6,8 @@
     "license": "GPL-3.0",
     "private": true,
     "scripts": {
-        "test": "jest --maxWorkers=3",
-        "test:verbose": "jest --maxWorkers=3 --verbose",
+        "test": "node script/lib/jest.js --maxWorkers=3",
+        "test:verbose": "node script/lib/jest.js --maxWorkers=3 --verbose",
         "build": "node build.js",
         "lint": "eslint . && prettier --check .",
         "fmt": "prettier --write .",