RFR: 8365017: The SegmentBulkOperations::copy method can be improved using overlaps

[Per Minborg]

This PR proposes to use overlapping memory areas in `SegmentBulkOperations::copy`similar ', similar to what is proposed for `SegmentBulkOperations::fill` in https://github.com/openjdk/jdk/pull/25383.

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Commit messages:
 - Add methods to ScopedMemoryAccess
 - remove file
 - Use overlapping copy

Changes: https://git.openjdk.org/jdk/pull/26672/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=26672&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8365017
  Stats: 156 lines in 3 files changed: 118 ins; 19 del; 19 mod
  Patch: https://git.openjdk.org/jdk/pull/26672.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26672/head:pull/26672

PR: https://git.openjdk.org/jdk/pull/26672