RFR: 8316304: (fs) Add support for BasicFileAttributes.creationTime() for Linux [v5]

[Severin Gehwolf]

> Please review this nio change which adds `BasicFileAttributes.creationTime()` support for Linux by means of the `statx` Linux specific system call. The patch does a dynamic lookup of the function and if it is available, uses it to set the support birth time capability in `UnixNativeDispatcher`. When `statx` is not available, it won't use it and fall back to the old behaviour on such systems. It should, however, compile fine on Linux systems not supporting the `statx` system call.
> 
> Testing:
> - [x] GHA (MacOS X failure seems unrelated)
> - [x] `java.nio` tests.
> - [x] Manual builds and tests on older glibc versions (2.17 => fallback, 2.28+ => works). Compiles fine and falls back to the not supported case as it was before this patch.
> 
> Thoughts?

Severin Gehwolf has updated the pull request incrementally with one additional commit since the last revision:

  Add support for nano seconds for btime on Linux

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/15792/files
  - new: https://git.openjdk.org/jdk/pull/15792/files/7aa251b6..643251db

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15792&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15792&range=03-04

  Stats: 19 lines in 2 files changed: 15 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/15792.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15792/head:pull/15792

PR: https://git.openjdk.org/jdk/pull/15792