RFR: 8349083: Factor out filename handling code from logging

[Zhengyu Gu]

Factor out filename substitution code from unified logging, so that it can be used elsewhere:

1. Make filename substitution consistent.  Support following substitutions cross JVM
```   
   %p -> pid
   %t -> timestamp
   %hn -> hostname


2. Reduce redundant code

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Commit messages:
 - Cleanup
 - More cleanup
 - rename
 - Clean up
 - Merge branch 'master' into JDK-8349083
 - Fix bug
 - Fix include
 - v2
 - v1
 - add new files
 - ... and 1 more: https://git.openjdk.org/jdk/compare/06ebb170...0dfc026c

Changes: https://git.openjdk.org/jdk/pull/23410/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23410&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8349083
  Stats: 322 lines in 7 files changed: 201 ins; 114 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/23410.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23410/head:pull/23410

PR: https://git.openjdk.org/jdk/pull/23410