DurationFormat: Add tests for durations with style: "digital", hoursDisplay: "auto" and zero hours

[sosukesuzuki]

The implementation of Intl.DurationFormat in WebKit (JavaScriptCore) has passed all test262 test cases, but we discovered two incompatibilities with the specification. This Pull Request adds tests addressing those issues.

The first one is described in bug 285078. A separator is printed erroneously for an unprinted hours value:

const df = new Intl.DurationFormat('en-US', {
  style: "digital",
  hoursDisplay: "auto",
});
df.format({hours: 0, minutes: 1, seconds: 2});
// expected: "01:02"
// actual  : ":, 01:02"

The second one is described in bug 285212. A negative sign is not printed:

const df = new Intl.DurationFormat('en-US', {
  style: "digital",
  hoursDisplay: "auto",
});
df.format({ hours: 0, minutes: -2, seconds: -3 });
// expected: "-02:03"
// actual  : "02:03"

Both issues occur when style: "digital", hoursDisplay: "auto", and the hours value is 0 or absent. For that reason, they are combined into a single test file.

[sosukesuzuki]

Chrome prints "1 day:01:02" for this, which is correct?

[sosukesuzuki]

esvu on CI fails but probably this PR isn't related

esvu ❯ version 1.2.16
JavaScriptCore ❯ Checking version...
esvu ✖ FetchError: request to https://webkitgtk.org/jsc-built-products/x86_64/release/LAST-IS failed, reason: certificate has expired
    at ClientRequest.<anonymous> (/home/circleci/test262/node_modules/node-fetch/lib/index.js:1501:11)
    at ClientRequest.emit (node:events:518:28)
    at emitErrorEvent (node:_http_client:101:11)
    at TLSSocket.socketErrorListener (node:_http_client:504:5)
    at TLSSocket.emit (node:events:518:28)
    at emitErrorNT (node:internal/streams/destroy:169:8)
    at emitErrorCloseNT (node:internal/streams/destroy:128:3)
    at process.processTicksAndRejections (node:internal/process/task_queues:82:21) {
  type: 'system',
  errno: 'CERT_HAS_EXPIRED',
  code: 'CERT_HAS_EXPIRED'
}
esvu ✖ Some engines were not installed.