RFR: 8369433: G1: Replace G1MarkScope with NMethodMarkingScope

[Francesco Andreuzzi]

On Wed, 8 Oct 2025 16:14:20 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> Replacing `G1MarkScope` with `NMethodMarkingScope`, since they have equivalent implementations.
>> 
>> Passes tier1 and tier2 (fastdebug).
>
> Marked as reviewed by tschatzl (Reviewer).

Thanks for the review @tschatzl and @albertnetymk.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/27697#issuecomment-3385665190