regular_expression: Improve ES2025 proposal-duplicate-named-capturing-groups logic

[leaysgur]

Done in #6847 , but there is room for performance improvement.

Original issue

> https://github.com/tc39/proposal-duplicate-named-capturing-groups Spec text is not updated yet, ongoing PR may be helpful. 👉🏻 https://github.com/tc39/ecma262/pull/2721 For now, `/(?.)(?.)/` is invalid syntax, name `a` is duplicated. With this change, we can use the same name if they are splitted by `|` and in the same `Disjunction` like `/(?.)|(?.)/`. But it still not allowed in some cases like `/(?|(?))/`, `/(?(?)|)/`, `/((?)|(?))(?)/`, etc... You need to track nesting level and `|` to mange scope. ### TODOs - [ ] Update count capturing parens logic to allow duplicates in certain cases - https://github.com/oxc-project/oxc/blob/aa7718ab7bf0544b21564658a919307022f8824a/crates/oxc_regular_expression/src/body_parser/state.rs#L51 - No need to change parser main logic - [ ] Update README - https://github.com/oxc-project/oxc/blob/aa7718ab7bf0544b21564658a919307022f8824a/crates/oxc_regular_expression/README.md - [ ] Update local tests - https://github.com/oxc-project/oxc/blob/aa7718ab7bf0544b21564658a919307022f8824a/crates/oxc_regular_expression/src/body_parser/mod.rs - [ ] Enable conformance tests - https://github.com/oxc-project/oxc/blob/aa7718ab7bf0544b21564658a919307022f8824a/tasks/coverage/src/test262/mod.rs#L103-L104

I'd like to take a stab at this!

[Boshen]

@preyneyv You may continue with https://github.com/oxc-project/oxc/pull/6847