RFR: 8292286: Convert PlaceholderTable to ResourceHashtable [v2]

Mon Aug 15 17:14:12 UTC 2022

On Mon, 15 Aug 2022 15:59:31 GMT, Coleen Phillimore <coleenp at openjdk.org> wrote:

>> This change converts the PlaceholderTable to ResourceHashtable.  It's much like the ResolutionErrorTable conversion.  This change has been performance tested with the previous set of testing with no regression.  It's also been tested tier1-3 and 4-7 with the other tables in my patch queue.
>
> Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use Symbol::maybe increment or decrement refcount.

Changes look good!
Thanks, Harold

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Marked as reviewed by hseigel (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9854