RFR: 8374945: Avoid fstat in os::open [v2]

[Jonas Norlinder]

> Eliminate unnecessary calls to fstat in os::open akin to JDK-8373647. This optimization reduces system overhead.

Jonas Norlinder has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - Fixes
 - Remove trailing whitespace
 - [Linux] Avoid fstat in os::open

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Changes: https://git.openjdk.org/jdk/pull/29152/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29152&range=01
  Stats: 7 lines in 1 file changed: 5 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/29152.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29152/head:pull/29152

PR: https://git.openjdk.org/jdk/pull/29152