RFR: 8367397: Improve naming and terminology in regmask.hpp and regmask.cpp [v5]

[Daniel Lundén]

On Fri, 12 Sep 2025 12:23:29 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> I vote for `RM_SIZE_IN_WORDS` because it is a constant, the same as if it was a value from an enum.
>
> Same as @dean-long : constants and enum values are generally `RM_SIZE_IN_WORDS`. Sometimes we also do `CamelCase`. Like for `LogBitsPerWord`. Underscore `_` is really only for fields.

Thanks, now updated

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PR Review Comment: https://git.openjdk.org/jdk/pull/27215#discussion_r2344100928