RFR: 8356127: (fs) UnixFileSystemProvider.implDelete could save a syscall in some cases [v3]

[Brian Burkhalter]

> Modify `UnixFileSystemProvider.implDelete` to attempt first to delete the file using `unlink` and, if that fails, fall back to using `rmdir` if the file is a directory.

Brian Burkhalter has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains four additional commits since the last revision:

 - 8356127: Change capability naming
 - Merge
 - 8356127: Add capability check for EISDIR
 - 8356127: (fs) UnixFileSystemProvider.implDelete could save a syscall in some cases

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25107/files
  - new: https://git.openjdk.org/jdk/pull/25107/files/17b67498..3814a184

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25107&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25107&range=01-02

  Stats: 13976 lines in 456 files changed: 7458 ins; 4062 del; 2456 mod
  Patch: https://git.openjdk.org/jdk/pull/25107.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25107/head:pull/25107

PR: https://git.openjdk.org/jdk/pull/25107