RFR: 8366272: The os::xxx APIs do not manage errno correctly [v5]

[Anton Artemov]

> Hi, please consider the following changes:
> 
> In this PR the handling of `errno` is improved by inspection of the codebase and fixing potential overwrites of `errno` by other methods. Potential overwrites are addressed using `ErrnoPreserver` functionality where necessary. 
> 
> Tested in tiers 1 - 5.

Anton Artemov has updated the pull request incrementally with one additional commit since the last revision:

  8366272: Fixed whitespaces.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28086/files
  - new: https://git.openjdk.org/jdk/pull/28086/files/d721128f..bc0c45f7

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28086&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28086&range=03-04

  Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/28086.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28086/head:pull/28086

PR: https://git.openjdk.org/jdk/pull/28086