RFR: 8253275: Remove unused methods after CMS removal

[Per Lidén]

On Thu, 17 Sep 2020 08:17:49 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> Static analysis shows a few examples of methods that are not used/implemented after CMS removal. We can purge them.
> 
> Testing: text searches over the code base, no hits; Linux x86_64 builds

Thanks for cleaning!

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Marked as reviewed by pliden (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/219