RFR: 8356107: [java.lang] Use @requires tag instead of exiting based on os.name or separatorChar property [v2]

[Brent Christian]

> For `java.lang` tests, use the `@requires` facility in place of checking the `os.name` system property or `File.separatorChar`.
> 
> Automated test results are omitted as expected.

Brent Christian has updated the pull request incrementally with one additional commit since the last revision:

  NonAnsiFileEncodingTest.java is no longer applicable

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25163/files
  - new: https://git.openjdk.org/jdk/pull/25163/files/c5a255a8..737b222d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25163&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25163&range=00-01

  Stats: 64 lines in 1 file changed: 0 ins; 64 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/25163.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25163/head:pull/25163

PR: https://git.openjdk.org/jdk/pull/25163