RFR: JDK-8285362: unify os::pause platform coding

Thu Apr 21 12:37:58 UTC 2022

The os::pause() coding in the different os_platform.cpp files is very close, so it should be unified at os.cpp .
Small differences : Windows uses Sleep, the other platforms use poll.
AIX used trcVerbose for some error/warning - like  output, the other platforms used jio_fprintf ; I think it makes sense to unify this on all OS to jio_fprintf .

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Commit messages:
 - JDK-8285362

Changes: https://git.openjdk.java.net/jdk/pull/8338/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8338&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8285362
  Stats: 116 lines in 5 files changed: 33 ins; 83 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8338.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8338/head:pull/8338

PR: https://git.openjdk.java.net/jdk/pull/8338