RFR: 8263998: Remove mentions of mc region in comments

[Calvin Cheung]

On Thu, 29 Apr 2021 16:49:47 GMT, Yumin Qi <minqi at openjdk.org> wrote:

> Hi, Please review the simple changes for removing the mc/MC mentioned in comments.  "mc" region was removed in fix of
>  https://bugs.openjdk.java.net/browse/JDK-8263002
> 
> Tests: local build.
> 
> Thanks
> Yumin

Looks good and trivial.

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Marked as reviewed by ccheung (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/3799