RFR: 8302734: Parallel: Remove unused LGRPSpace::_invalid_region

[Albert Mingkun Yang]

On Fri, 17 Feb 2023 11:01:54 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

> Trivial removing dead code.

Thanks for the review.

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

PR: https://git.openjdk.org/jdk/pull/12615