[jdk21u] RFR: 8316468: os::write incorrectly handles partial write

[Man Cao]

Clean backport to fix bug in os::write() that could cause heap dump corruption.

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Commit messages:
 - Backport 7ce5bd159024e70f5a997c47ed2ce962d6e6091b

Changes: https://git.openjdk.org/jdk21u/pull/176/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u&pr=176&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316468
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u/pull/176.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/176/head:pull/176

PR: https://git.openjdk.org/jdk21u/pull/176