RFR: 8285364: Remove REF_ enum for java.lang.ref.Reference [v2]

[Albert Mingkun Yang]

On Thu, 21 Apr 2022 11:30:20 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> Simple rename and some comments update.
>> 
>> Test: build
>
> Albert Mingkun Yang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   review

I have taken the commit from Stefan and updated the title.

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PR: https://git.openjdk.java.net/jdk/pull/8332