dateIsoWeek depends on the timezone of the machine running the tests

[joeframbach]

Describe the bug
At https://github.com/capricorn86/happy-dom/blob/master/packages/happy-dom/src/nodes/html-input-element/HTMLInputElementDateUtility.ts#L17-L19, date.getDay() is dependent on the timezone of the machine. The results are inconsistent.

To Reproduce
Steps to reproduce the behavior:

$ TZ="UTC" npm run test -- --no-cache --force
happy-dom:test:  Test Files  89 passed (89)
happy-dom:test:       Tests  2344 passed (2344)

$ TZ="US/Pacific" npm run test -- --no-cache --force

happy-dom:test:  FAIL  test/nodes/html-input-element/HTMLInputDateUtility.test.ts > HTMLInputElementDateUtility > dateToIsoWeek() > Returns the ISO week number
happy-dom:test: AssertionError: expected '2021-W02' to be '2021-W01' // Object.is equality

happy-dom:test:  FAIL  test/nodes/html-input-element/HTMLInputDateUtility.test.ts > HTMLInputElementDateUtility > IsoWeekToDate() > Returns the ISO week number
happy-dom:test: AssertionError: expected 2020-12-29T00:00:00.000Z to deeply equal 2020-12-28T00:00:00.000Z

happy-dom:test:  FAIL  test/nodes/html-input-element/HTMLInputElement.test.ts > HTMLInputElement > get valueAsDate() > Should return valid date for type 'week' with valid value
happy-dom:test: AssertionError: expected 2023-05-30T00:00:00.000Z to deeply equal 2023-05-29T00:00:00.000Z

To reproduce the root cause:

$ TZ="US/Pacific" node -e "console.log(new Date('2021-01-03').getDay())"
6

$ TZ="UTC" node -e "console.log(new Date('2021-01-03').getDay())"
0

Expected behavior
Tests should pass anywhere in the world.

Screenshots
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Device:

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Latest version

Additional context
Add any other context about the problem here.

[capricorn86]

It should be possible to set timezone for the entire NodeJS process by just adding the environment variable TZ=utc.

Example 1:

     {
           "scripts": {
                 "test": "TZ=utc jest"
            }
     }

Example 2:

process.env.TZ = 'Europe/Amsterdam'