RFR: 8280374: G1: Remove unnecessary prev bitmap mark

[Hamlin Li]

On Fri, 21 Jan 2022 08:45:41 GMT, Thomas Schatzl <tschatzl at openjdk.org> wrote:

>> In JDK-8278917, the prev bitmap is used to mark evac failure objs, so at the post of evacuation, the evacuation failure objects are already marked during pss evacuation, so there is no need to mark them again in remove self forwardee phase.
>
> Testing seems all good (tier1-5)

Thanks @tschatzl @albertnetymk for your reviews.

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PR: https://git.openjdk.java.net/jdk/pull/7153