`RegExp.prototype[@@split]` calls the `hasIndices` and `dotAll` getters via the `flags` getter[1]. If these getters are overwritten, observable side effects may occur. However, the fast path skips these getter calls. [1]: https://tc39.es/ecma262/multipage/text-processing.html#sec-regexp.prototype-@@split
Pull request: https://github.com/WebKit/WebKit/pull/28835
<rdar://problem/128849967>
Committed 279905@main (b03cf953dce9): <https://commits.webkit.org/279905@main> Reviewed commits have been landed. Closing PR #28835 and removing active labels.