Allowing BC era timestamps in fromAbsolute (#6541)

[KimPeeters]

Closes #6541

✅ Pull Request Checklist:

• [x] Included link to corresponding React Spectrum GitHub Issue.
• [x] Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• [x] Filled out test instructions.
• [x] Updated documentation (if it already exists for this component).
• [x] Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

The unit test should cover this. By hand:

import { fromAbsolute } from "@internationalized/date";

console.log(fromAbsolute(-62135596800001, "UTC").toAbsoluteString());
// ^^ should return:  0000-12-31T23:59:59.999Z