RFR: 8353727: HeapDumpPath doesn't expand %p [v4]

[Kevin Walls]

> 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).

Kevin Walls 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 five additional commits since the last revision:

 - Merge remote-tracking branch 'upstream/master' into HeapDumpPath_pid
 - test feedback
 - length checking update
 - Chris feedback
 - 8353727: HeapDumpPath doesn't expand %p

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/24482/files
  - new: https://git.openjdk.org/jdk/pull/24482/files/40c67a0c..09f66542

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=24482&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=24482&range=02-03

  Stats: 11976 lines in 335 files changed: 8329 ins; 2524 del; 1123 mod
  Patch: https://git.openjdk.org/jdk/pull/24482.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24482/head:pull/24482

PR: https://git.openjdk.org/jdk/pull/24482