RFR: 8333884: MemorySegment::reinterpret removes read-only property [v3]

[Per Minborg]

> This PR proposes to retain the read-only state when any of the `MemorySegment::reinterpret` methods is called.
> 
> Previously, the read-only state was lost and the returned `MemorySegment` was always writable regardless of the original segment's read-only state.

Per Minborg has updated the pull request incrementally with one additional commit since the last revision:

  Add read-only comment on asSegment too

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Changes:
  - all: https://git.openjdk.org/jdk/pull/19629/files
  - new: https://git.openjdk.org/jdk/pull/19629/files/538eb2ed..bc0ade8a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=19629&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=19629&range=01-02

  Stats: 19 lines in 1 file changed: 13 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/19629.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19629/head:pull/19629

PR: https://git.openjdk.org/jdk/pull/19629