RFR: JDK-8314211: Add NativeLibraryUnload event [v2]

[Martin Doerr]

On Tue, 15 Aug 2023 15:33:32 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> [JDK-8313251](https://bugs.openjdk.org/browse/JDK-8313251) introduced a a NativeLibraryLoad event that provides us more detail about shared lib/dll loads.
>> There should be a similar event for unload operations of shared libs.
>
> Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Simplify os_windows code

LGTM.

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

Marked as reviewed by mdoerr (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/15272#pullrequestreview-1579248060