RFR: 8272147: Consolidate preserved marks handling with other STW collectors

[Guoxiong Li]

Hi all,

This patch removes the class `markSweep.hpp::PreservedMark` and uses the shared `PreservedMarksSet` instead.

In order to keep the meaning of the field `_preserved_marks` in `markSweep`,
I need to use `OopAndMarkWord` explicitly. So I move `OopAndMarkWord` out of `PreservedMarks`.

Tests:
`hotspot:tier1` passed locally (x86 & linux).

Thanks for the review.

Best Regards,
-- Guoxiong

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Commit messages:
 - JDK-8272147

Changes: https://git.openjdk.org/jdk/pull/14274/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14274&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8272147
  Stats: 70 lines in 5 files changed: 19 ins; 34 del; 17 mod
  Patch: https://git.openjdk.org/jdk/pull/14274.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14274/head:pull/14274

PR: https://git.openjdk.org/jdk/pull/14274