RFR: 8353727: HeapDumpPath doesn't expand %p

[Zhengyu Gu]

On Mon, 7 Apr 2025 09:05:34 GMT, Kevin Walls <kevinw at openjdk.org> wrote:

> This is a long-standing oversight: HeapDumpPath does not recognise %p for pid expansion.
> The default filename uses a pid (e.g. java_pid1676937.hprof) but HeapDumpPath does not.
> It has always done a manual "root plus pid plus extension" on the default filename only, and
> should move to using Argument::copy_expand_pid() like we do with other such filenames.
> 
> 
> We also assumed the default filename is not a directory (which is very very likely, but doesn't have to be true).

@kevinjwalls I have [JDK-8349083](https://bugs.openjdk.org/browse/JDK-8349083) to address similar issues. 

AFAICT, there are 3 separate code to handle filename expansion and logging has the most complete support, It will be nice to unify them.

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PR Comment: https://git.openjdk.org/jdk/pull/24482#issuecomment-2783181347