As can be seen from the first round of testing in PR #15864, trying to update Puppeteer beyond version `19.0.0` completely breaks testing in Firefox. Curiously it does work locally when the `--noChrome` flag is being used, so it seems to be an issue with running tests in both Chrome *and* Firefox in parallel.

We need to fix this, likely by making some adjustments to our test-suite, such that we don't get "stuck" on an older version of Puppeteer without being able to update. (A temporary work-around could also be to disable testing in Chrome.)

describe: "Run specific reftest(s).",
      type: "array",
    })
    .example(
      "testfilter",
      "$0 -t=issue5567 -t=issue5909\n" +
        "Run the reftest identified by issue5567 and issue5909."
    )
    .option("unitTest", {
      default: false,
      describe: "Run the unit tests.",
      type: "boolean",
    })
    .option("xfaOnly", {
      default: false,
      describe: "Only run the XFA reftest(s).",
      type: "boolean",
    })
    .check(argv => {
      if (
        +argv.reftest + argv.unitTest + argv.fontTest + argv.masterMode <=
        1
      ) {
        return true;
      }
      throw new Error(
        "--reftest, --unitTest, --fontTest, and --masterMode must not be specified together."
      );
    })
    .check(argv => {