RFR: 8354189: Remove JLI_ReportErrorMessageSys on Windows

[Matthias Baesken]

JLI_ReportErrorMessageSys is not used any more on Windows, so we can remove it and make it UNIX-only (there a still a few remaining usages).

-------------

Commit messages:
 - JDK-8354189

Changes: https://git.openjdk.org/jdk/pull/24563/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24563&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8354189
  Stats: 77 lines in 3 files changed: 4 ins; 73 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/24563.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24563/head:pull/24563

PR: https://git.openjdk.org/jdk/pull/24563