This reverts commit 6b682148.

Reason for revert: Cause CHECK violation in https://bugs.chromium.org/p/chromium/issues/detail?id=1356838 
Original change's description:
> [intl] Return "UTC" instead of "Etc/UTC" or "Etc/GMT" as DefaultTimeZone
>
> Refactoring the code dealing with TimeZone Canonicalization.
> Change CanonicalizeTimeZoneName from return MaybeHandle<String> to Handle<String>
> Move TimeZoneId from JSDateTimeFormat to Intl and return Handle<String> instead of Handle<Object>
>
>
> Bug: v8:13112
> Change-Id: I678b0e0d407e5e4e9dd8b7120c0e99e7e2d9c5ea
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3833435
> Reviewed-by: Shu-yu Guo <syg@chromium.org>
> Commit-Queue: Frank Tang <ftang@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#82505}

Bug: v8:13112
Change-Id: If4df4bc19b5d1a02c51e2c944abaca8a25b76a1e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3863883Reviewed-by: Shu-yu Guo <syg@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#82796}